I'm 21 weeks pregnant (in Dallas, TX) and I've had no prenatal care due to having no insurance.?

I'm 21 weeks pregnant (in Dallas, TX) and I've had no prenatal care due to having no insurance,Now that my insurance has kicked in, I've been frantically looking/calling everywhere for an OB that will accept me. the problem is, I've called and called and everyone keeps telling me no one will take on new OB patients after 20 weeks gestation. Is this true? How can that be? What should I do? Should I lie about my LMP just to get in ? I mean I'm really freaking out (if you can't tell) Someone please help?