FMLA being denied by OBGYN

I'm soooo mad!! I want to take my FMLA now, since I'm in constant pain and the stress is affecting my pregnancy (I had clumps of blood coming out of my cervix and apparently stress is what caused it) anyways, I called my doctor to see if they'll just sign the paperwork now so I can take my leave already and the receptionist told me no the doctor won't sign it until I'm at least 36 weeks. I was told by the OB triage nurse, and my own boss to just go on my leave already and this jerk won't let me :( and I can't find another doctor to see me since I'm already 30 weeks