Hi, So Basically I've Missed My Period Twice In A

Hi, so basically I've missed my period twice in a row and I'm on the pill and don't know what's wrong. It's happened to me before and my period has come back but I'm afraid it won't and something is wrong because it shouldn't be doing that. Yes I'm sexually active but I've never missed any of my pills and we always use a condom. If I was pregnant wouldn't I feel different because I feel perfectly fine and normal and look it too. There has to be something else messing with my cycle, so please could you help and tell me what could be the problem. Thanks.