I also agree that daycare can be very good for a child. A babysitter who does nothing with them can be a very bad thing, but a good daycare center that has more of a preschool environment can really expedite their growth and learning.
When my daughter was younger (she's a bit over 3 now) I spent a lot of time with her home alone. It was VERY boring at times... sometimes depressing. I was in a new city with no family to watch her and no friends, so that's probably what made it worse. You need some adult time and adult conversation to keep you sane.
Find out what you want to do with your life and make arrangements for it to work for you. No excuses
I went back to school while having a young child. Now I work full-time while taking courses at night. Yes, she does go to daycare full-time right now... but she is a bit older now and has a good time there. And I know she learns a whole lot more there interacting with 20 different kids and other adults than she would sitting home with a depressed dad who is wallowing in self-pity because he never gets to leave the house!