Hi E.,
I can certainly empathize. I went through the same thing with my son, only his preschool and his teachers were proactive, supportive, firm, but loving, and worked with us to reinforce what we were doing at home to eliminate this behavior. As child care specialists and educators, they understood that this behavior does occur in preschool children, and although they made it clear to my son (as well as to the other kids who were hitting in the class) that it was not okay, they did not ever label him as bad or make me feel like I was a bad parent or doing something wrong. We worked together on this, and it is no longer a problem.
Sorry if this gets long or seems like too much information. I just really feel your frustration and want to offer some things that may help.....not sure if any or all apply, but take what might work for you. Please do not beat yourself up. You are obviously a good and loving mom. Your son is 3 and exhibiting behaviors that are commonly seen in preschool children. While we certainly would never condone hitting or consider it acceptable, we must understand that our children are young and learning how to "be in the world" and we are here to help teach them.
First, how is your son's health? Does he have on-going health issues? When was his last physical? Did you talk with your pediatrician about the hitting? Most schools require an up to date physical and a doctor's signature indicating that your child is well and can handle a preschool setting.
At home, I would, as another mom wrote, seriously monitor what he watches on tv. So many things that might seem okay on the surface are just not good for preschool children. And if you think they aren't paying attention or picking up on things, they do! I have had to institute rules in our household for the older kids(older teens)that when our 4 year-old is in the room, there can be nothing with swearing, violence, etc., and this includes the vast majority of PG movies! Basically, limit him to PBS, Sprout, Disney preschool (not the tween stuff), and Noggin. Shows on these channels are written especially for preschool children and try to model and reinforce positive values and appropriate social behaviors.
But it's not only what he watches; it's HOW MUCH he's in front of tv/videos/computer screens, etc. I let my son watch a few shows and then say, "tv time is done for the day. Let's do something else now." You might get a fight and some tears, but you control the remote!
When small children are allowed to sit in front of a screen and passively receive information for too long, it truly does negatively affect their attention span (which is already very short, understandably) and their ability to process information.
At this age, our children should be actively exploring and manipulating things in their world, e.g., doing puzzles, drawing with crayons, making things with clay or play-dough, building with blocks, etc. Reading with your child and just having conversations with him are much more important to his brain/behavior development than any "educational" program or video. Not sure if this is a factor in your case, but thought I'd mention it as it is so important.
I also found with my son that he also needs at least some "running time" just about every day. It might be going on bike ride, going out and throwing a few baseballs, swimming, going to the park, whatever. Even 15 minutes of physical activity can make a differnce. Our little ones need some safe outlet where they can exert all of that energy they have. I know this is hard to do every day, and some days, it just might not be possible, but it doesn't have to be very long. On the days he is at preschool, your son should have at least some playground time, so it's covered on those days.
Sleep. Make sure he is getting enough. You know your child best, but experts usually say between 11-13 hours for this age group. If he doesn't sleep this much through the night, try to have him nap, even if he has "given up" on naps. Most often, it is us parents who "give up" on naps because we don't want to fight with the children about it when they resist. He should at least have some quiet or down time, if he is not sleeping enough through the night.
Nutrition. Check his diet to see if you can determine any particular foods that might affect him negatively. Although many people say it is a fallacy, I believe processed sugar and foods do affect children's behavior.
You may want to try elimiating some of the common culprits like overly processed sugared cereals/cereal bars and replacing fresh fruits for high-sugar content juices, etc. and see if this helps.
Someone mentioned the book, "Hands Are Not for Hitting." It is an excellent book, and it was part of our strategy. We read it over and over, and even after the hitting behavior dropped off, we'd read it once in a while for reinforcement. It is short, sweet, but says all it needs to say on this subject!
You may want to try some small group playdates (2-3 other children) and monitor your son's behavior during the interaction. If he hits, remove him immediately, and firmly say, "We don't hit. Hitting hurts." Set him away (safely) from you and the others and don't give him any other attention for 3 minutes. At the end of the time-out, say, "I'm sure you're ready to get back and play and use nice hands. Let's go, so you don't miss the fun!" Do this consistently every time he hits. It may even mean leaving a playdate or party or other fun activity, but it won't take long, if he has to leave an activity he loves.
Whenever you observe your son using "nice hands" or other socially appropriate behaviors, genuinely PRAISE him then and there...."I like how you shared your toy with Tommy" or "You're doing such a great job using nice hands today!"
Behavior that gets reinforced gets repeated. You want the "good" behaviors to be repeated.
Now, about the school. It is a little concerning that the teacher handled the situation in this way on your child's FIRST DAY in preschool. I'm not sure about your school, their policies, the teacher requirements, but ideally, the teachers and the administration should be willing to work with you to develop a very specific plan to deal with this behavior. Pick-up and drop-off times are very hectic and not a good time to talk to the teacher about this. Ask her when you can schedule a time to talk, preferably in person, to come up with a plan. You may also want to talk with the administrator and share your concerns. Check with the parent handbook for the school's policies on hitting. Some schools do have very stringent rules about this. The key is to get all of the adults (mom, dad, grandparents, teachers, etc.) who have contact with your child working from the same page.
Please know that you are not alone. Many, many moms have struggled with this. It takes consistency, firm redirection, tons of patience and love, but it can be done.
Best wishes to you and your family as you work through this issue! It does get better!
J. F.