IVF friends! Quick question

Hey ladies. I have a quick question. I started BC (last Sunday) for my IVF cycle and I have noticed that I have been crampy lately and have sort of a vibration feeling on and off in my Uterus area.. I have not been on BC for 6 years so is this a normal reaction to taking BC? Should I call and ask my doctor?? I am just worried that it could be something else and delay my IVF cycle ( I know paranoid but I can't help it). Thanks for listening!