FMLA before baby

So my work has great pregnancy benefits. I was approved to go out four weeks before due date for STD and FMLA. 
Around 30 weeks I was miserable everyday and could tell I wasn't performing like I should. 
Last week I called the company that does our leave and told them to go ahead and mark me out of work due to complications and inability to perform my job. 
I have heart palpitations, migraines, dizziness, and high BP readings after work. I'm scared of getting pre-e because I'm overweight and symptoms I'm having. 
Anyway, so last week I was 34weeks and know FMLA covers 12 weeks of job protection before and after baby. The law outline is so vague it says "prenatal care, serious medical condition and incapacity due to pregnancy" 
Anyone have it denied or approved before baby? 
I'm not going to work and my claim is pending. I'm having anxiety attacks scaring myself it will be declined and I'll be fired.