Glad to hear things are getting better for you!
I did not read everyone's suggestions, but thought I would say I am glad you are getting out and having some fun.
I would suggest you always remember God is with us and can help us with anything! ;-)
I would also suggest you make some friends in the women's Bible study. If this study does not appeal to you or the women don't click with you, find another one. There are a lot of churches around and I am sure you could find a group you will feel comfortable with.
As for your son he also is at the age where they start being interested in making friends and seeing the world beyond themselves. Now is a good time for him to be experiencing a mother day out or a preschool.
He also needs to learn to entertain himself. I find it appalling that many people think they have to entertain their children. The kids can learn to play with Legos, tinkertoys, or color alone for short periods without needing adult interaction. The adults can be nearby, but they do not need to entertain the child all day.
Kids have wonderful God-given imaginations. They can create great stories with them and a few cars, trucks, some dirt. A playdough activity will help spark that too. Let your son start playing alone in the mornings while you wash dishes. You may have to train him to think like this since he may already think it is your job to entertain him all day.
Make him help you with housework also. He can fold laundry, dust low tables, carry things for you. Mine never had to do beyond their age and ability, but at this age they started helping me by folding kitchen towels and small things. It is part of the learning process and teaching them a household is a team effort--not a slave/master thing, or a designated role thing. For example my dh will sometimes help me fold laundry or wash dishes and I can mow the yard or help clean up debris.
I stayed home at different times with my kids. I know how sometimes you can feel like you are going to go crazy. We were meant to have social interaction, set goals, have hobbies, etc. I had a 5, 4, and baby and we had a lot of fun together. But they were already getting training at that age of how to interact with others and how to help run a household. ;-) I did things I could do at that point. I went to Bible study and church. I did cross stitch and painting. I worked on areas of our house--repainting the hallway and bathroom. But I did not spend every single day doing nothing but entertaining kids and housework. That would drive anyone nuts. LOL
Good luck and hang in there!