You are lucky to have your mom watching him. Another thing you have to think about is...would you actually be the person YOU want to be if you stayed home. I know for me...I loved the idea of not having to get up early and drive to work, and staying home with my kid all day everyday and playing. But...there are downpoints too. People who are stay at home moms often have only 1 income and so staying on budget is harder, and being at home all the time is fun, but...sometimes, especially with only one income...that's exactly what you could be doing. You might not have the income to go to alot of play places and keep busy because of the fixed income. Also...personally, I feel better working and feeling like I'm making a difference somewhere other than my home. I like being needed elsewhere and making a difference in my work and taking pride in what I do. I feel like it's all mine and I don't have to share it with anyone. It's sort of selfish in a way, but for me, because I feel like I make a difference somewhere other than my home, I feel happier in myself and I can be a better mom when I have to put my Mom hat on. I also think that quality is better than quantity. I don't underestimate how much people who stay at home do. I can't do that much work all the time, so I go to work to relax and get peace time from my home life of cooking, cleaning, taking care of everyone else, life lessons for your child, etc. So, take comfort in working as long as you don't have the option to stay home.
My hubby always said (and still does) that he'd be fine with one of us staying at home. He'd be doing it if there was a way for me to bring home more money than he does. I've always had that option, but many things kept me in the workforce. You have a few hours in the evening with your child and the weekends. Make them count...make them quality. And, if you save your work until after your little one goes to bed, you'll feel more accomplished as a mom. If you cram that time full of attention for your son, you could probably even put him to bed a little earlier everynight and then, you'll even have a little extra time in the evening to get your tasks completed.
I think most mom's evenings are pretty similar. Cooking supper, playing, cleaning up, playing chauffer, laundry, putting kids to bed, cleaning more, work...etc. Most moms don't get time for themselves until way after the kids are in bed, and by then...you're so tired that we just go to bed too. Not much time for being lazy, etc.