Baby kisses- I just went through your "what ifs" so here's what happened to me: I normally have to take provera to start my period and it really can vary as to how long after your last provera pill you start your period. Mine would typically start in 3-5 days after the last pill. However, my OB put me on femara (5mg) and I didn't respond. None of my follicles matured so I was given provera to induce a period and try something else. I took provera and my period never came. The OB makes you wait two weeks to ensure you really aren't going to start and then made me take another round of provera (yes, back to back). After finishing the second round of provera I had a super light period and then started clomid. My OB wouldn't let me start any fertility meds until I had a period.
The OB said that sometimes it takes two rounds to start, but had never happened to me before so I was a bit freaked out.
I had no side effects from femara except for a few hot flashes. Good luck!!