T.M.
Children don't get cheaper as they get older. If you are truly struggling and questioning your ability to raise the child now, that isn't going to go away or get easier. You are guaranteeing that both you and the child will be financially limited for years to come, plus you are raising the child as a single parent rather than as a intact family. This is an additional loss for the child.
I don't say any of that to be hurtful. I know that this has to be one of the hardest choices you've ever considered in your life. You are being unselfish and loving to consider this option as it likely is the best thing for the child.
I would not go through the state social services if you want to place the child for adoption...that can end up with all sorts of negative consequences for both of you (placing the child in foster care, abandonment charges for you, etc...things never go smoothly with that route.) However, I can recommend a wonderful adoption agency that has offices in Tampa and Orlando. They are caring and kind, and make sure that the biological mother is cared for and gets counseling. They will do open adoptions so you can remain a part of the child's life if you choose.
Bless you for being willing to put your child first and truly be a mother.
http://www.heartofadoptions.com/
(If you use this agency, I highly recommend you ask for Nicole Ward.)
Best wishes and I will keep you in my prayers.