Hi Antionette,
Welcome to mamapedia!
Well, I think your sense of wanting to be protective of your son (regardless of if he's your 1st or 21st) is what makes us mamas!
Are you OVER-protective......I think it depends. My goal as a mom, was to teach my daughter how to become an independent, competent adult who can make good decisions.
Your son is only 2 and you live in the 3rd largest city in the US - and in a particularly "urban" section of the city (me too.... hence my moniker). My daughter is 11 1/2 and it wasn't until we moved to Missouri last October that I started letting her do wild and crazy things - like stay in the book section of Target while I went to get toilet paper.
now - she can read a city bus schedule, and get on the blue line going the right direction.... and she can get to the correct terminal of O'hare and even figure out a gate change......gosh, she could do those things by the time she was 6 or 7. But, she'd NEVER stayed alone in the house, wasn't allowed to go outside (even to get the mail) unless I was grabbing distance from her, and ABSOLUTELY would have always had to be with an adult. Different kids learn different skills depending on where they live.
Now - you call every hour to check on him.... why? Do you feel like your mom, sister or aunt can't watch him as closely as you? That's where I see the breakdown. it's your job to put him with caretakers who will love him and take care of him and see to his safety..... but you have to let him learn that others can take care of him too. Otherwise he'll grow up not learning how to accept help from the "right" people and you'll open him up to not being "streetwise", which can be dangerous.
2 years old IS kind of young for daycare (and this from a working mom, who put her daughter in daycare at 8 weeks!!!!!). So, if you can swing it..... keep him home with you another couple years.
But - enroll him in some Park District programs. let him scrape his knee, or get a shiner from throwing a ball around. Heck, even stiches or a broken arm will TEACH him how to heal and what his limits are.
And, most importantly have FUN with him. Make sure you aren't teaching him that life is scary and that he can get hurt. Teach him that life has risks and that he has to be careful - while he has the time of his life!