Help!

Celeste
Stopped my birth control 9.30.14 that same day I started my period and it lasted until 10.4.14, I had been TTC the whole month of October. My next period was supposed to start 10.30.14 it's now 11.13.14 and I still haven't started my period I'm 15 days late. Has anyone ever stopped there bc and hasn't started there period for a while?  I've taken multiple tests and they've been negative but it's been a while since I've taken one and I don't know what I should do I had regular periods when I wasn't on birth control so I figured they wouldn't be this off from getting off of my birth control.