@singlemom00,
Well, first of all, I think you should get child support. It's not about you, it's about providing for the baby. It will help throughout the child's whole life - food, clothes, bed, medicine, lessons, bike, schooling, etc. Don't deny your child the financial support he deserves. Secondly, if you go on assistance, they will INSIST you go after him for child support. If you go back to work, you will need $$ for daycare - it's no longer cheap!
You are in a similar situation to one of my nieces, who has since met and married a lovely man and had another child with him. She didn't go after child support either, and neither did I, which I regretted later on for my daughter's sake.
As far as sole custody, I don't think you'll have a problem. You need to talk to Legal Aid in your area about that IF you're going for child support. He likely won't challenge your bid for sole custody, but he should contribute to your child's life and expenses.
My daughter receives over $900 for two kids (support), plus 50% of the daycare (they earn about the same money). It's all based on income, here anyway.
Think long and hard about it, singlemom00... you don't want to make things harder for yourself. And it may well be that his family will welcome this child... would you not want your child to have a(nother) grandma, uncle, cousins, etc? Family holidays can be wonderful. They could also be a big help to you.