Second Trimester: finding prenatal care?

I'm almost 21 weeks along and have had no formal prenatal care. I've taken prenatal vitamins since I found out I was pregnant, but wasn't sure if I wanted to terminate my pregnancy or not, then there was an issue of waiting for my health insurance. Now I've contacted all the OBGYNs in the area and nobody will take me because I'm high risk and too far along. I deserve prenatal care and need it, where do I go? and why exactly am I high risk? Do they feel like they are liable at this point because I'm so far along? I never thought I'd run into an issue like that. Both of my reasons are both understandable for waiting so long and I know that other women have been in my position before. any suggestions?