S.B.
Contact a lawyer. It doesn't matter if you are married or not - if he is the father and he is on the birth certificate (or found through dna, etc) then you are entitled to child support. Some people don't want the father on the BC since it gives them legal rights (in addition to legally enforceable child support).
Here is a good web site re: michigan child support
http://www.michigan.gov/dhs/0,1607,7-###-###-####_5528-10...
and here is an excerpt from the site:
Establishing paternity by including the father on the birth certificate gives a child born outside of marriage the same legal rights as a child born to married parents.