Birth control & period!

Okay so I got birth control on may 15th. I think I actually took it for a week in a half and I didn't like what it was doing(it got me eating like crazy, I gained some weight) so I stopped taking it now its been 10 weeks and I haven't gotten my period at all. I've missed a total of 3 periods.. (I've had sex maybe a max of 3 times but he pulled out) can someone please tell me what could be happening ??