I just accidentally deleted everything I wrote. Long story short...
You WILL get through this.
Good for you for expressing yourself and asking for help.
Your number one job is to love and care for the children, everything else is secondary.
If you are not part of a mom's group, find one. This serves a couple of purposes: it gets you out of the house to get a fresh perspective. The kids can play with other kids while the mom's talk out their frustrations and exchange ideas on how to handle the terrible 2s, 3s, 4s, etc. (And wonderful 2s, 3s, 4s, too!)
Find a way to get a break...taking 20 minutes to take a bubble bath when your hubbie gets home and the kids are in bed. Take a walk. Get out of the house by yourself on for an hour on the weekend. Whatever makes you happy, do it. This renews your spirit and when you feel happy with yourself, you feel stronger and ready to love your 2 yo again.
Ask your hubbie to have a man to little man talk with your son. In understandable terms of course. Dad can play and roughhouse with your son, then have a talk. (You and your husband can decide what the "talk" will be. Your husband's job is to protect you and take care of you, and this may help. Make sure your husband and you are a team when it comes to discipline. If your 2 yo disrespects you in front of your hubbie, then your hubbie needs to stand up for you and let your son know that this is unacceptable behavior. Then have your husband put him in time out and if he won't stay in his time out chair then he should be "held" in the time out chair. Of course the restraining does not hurt the child. It is to show him who is in charge. Mommy AND Daddy are in charge TOGETHER. Two to 3 evenings of this and you may see a difference in behavior. When your son sees your husband respect you like this, he may follow suit.
This is just the surface of some advice but hopefully some of it will help you. I watched a lot of "SuperNanny" when my kids were little and it helped me to see that routines and time-outs done the right way can really help!
Also, if your son hits you, show that it hurts you. I mean that it hurts your feelings. this hurts you and it makes you feel sad inside. Show expression in your face and body language. This may get a better response than getting angry.
Love and Logic is good. Remember to be empathetic towards your son when he makes poor choices. "Too bad you made that choice. You will need to sit in your chair and take some time to think about that" etc etc
BTW for whatever it is worth, I bet your son still sees you as his beloved Mommy, and not a cook or a housekeeper.
Hang in there!!!!