I have to pay child support $750 per month,but all I pay is $500, do I
go in jail if I don't pay all?

If you do not pay your child support you can go to jail. Maybe you
need to take it in front of a judge to see if he will lower your child
support payments. $500.00 a mont are you on disability? Beucse if you
are able to work then they can expect you to keep a full time job to
make your payments.

I do not know where you live so i have pulled up a site that has some
generall information.

The Connecticut Child Support and Arrearage Guidelines are state
regulations which provide a mathematical formula to set the child
support payment amount. The Guidelines use the combined income of the
mother and the father and the number of children to set a child
support amount.

The court will also enter a medical insurance order for the minor
children if it is available through an employer for a reasonable cost.
The court may also order one or both parties to apply for, and
maintain, medical coverage through the HUSKY PLAN. The guidelines also
provide for the allocation of un-reimbursed medical costs between the
parties.

The guidelines also provide a mathematical formula for allocating
qualified childcare costs between the parties.

Judges and family support magistrates must follow the guidelines
unless they make an exception in their ruling and tell you why they
are ordering a different amount. These exceptions are called
"deviations."

The amount of the child support order can change. Because child
support payments are based on income, the support amount may change as
the circumstances of the parents change.

http://www.jud.state.ct.us/faq/child.html

I have hepatit C and tyroid, and I can't work so much becouse I get verry izy tierd

Can i please get the state in which you live in so that i can find
your specifi information.

Why don't you apply to the court for a "variation" to  your child
support amount? If you have medical proof that you must reduce your
work hours, then there's a good chance the judge would lower the
amount. Good luck!!

Steph53