I've been on birth control for a few months now, my boyfriend and I had unprotected sex a couple weeks ago and I haven't been taking my birth control regularly sometimes il forget to take it for a few days at a time. So a couple days after sex I bled brown blood and a little red for two days and it suddenly stop. I haven't taken any pills just to see if my period would come because usually when I stop taking birth control my period would come two later or three days but nothing has happen. I've been having some mild cramping on and off increased appetite, a little nauseated fatigue. I want to know could this be a side affect to the birth control from stop taking it. Or could this be early stages of pregnancy and should I wait to take a test.

If you are taking the birth control so poorly, a few days missed all the time, it is very likely that the birth control has little or no effect. So yes it could be either. You just have to wait to test.

You need to wait till your period should happen, and then wait 14 days more to test. Test with first urine of the morning