Get a lawyer. You need everything in writing, especially that regarding who has custody, child support payments, etc. The amount of child support depends on who has the child which percent of the time, I believe 50/50 means no child support, but it doesn't sound 50/50 to me. You may be entitled to something, but that also depends on the financial situation of those involved.

A friend of mine was going through an amicable divorce and decided to consult a lawyer just to make sure she was getting enough child support. Turns out her ex was not paying enough, both because they didn't know enough about the legal system. Talk to a lawyer, I know there are lawyers who will consult for free the first time and lawyers for low-income/disabled people.

I love you and am sorry this has happened, but this seems like an improvement from the previous situation! *hugs*