worried😔

I'm really worried that I can't have anymore kids. I'm 22 and my only living child is almost 4. I tried with my now ex before for a while to have another baby after my miscarriage but it never happened and every serious boyfriend I've had since has came in me and yet nothing. I wanted to get checked at the dr but she said she couldn't do such test and was going to refer me to a gynecologist but I guess never did. Now my Medicaid has went to just family planning which doesn't really help with anything other then birth control. Now I'm not sure what to do to find out if I can even still have kids.😢