FMLA--help!!

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Anyone that works in the US can you help me find where the rules are for the FMLA? My claim is pending and they never contacted me so I called and they said oh just tell us when you deliver. I specifically put in my claim for a couple weeks ahead of time due to many reasons. What gives my company the right to tell me I have to work up until the due date??
I go into the doctors tomorrow and will ask for paperwork to be sent but still, by law I at least get unpaid time they shouldn't mess with that!