on birth control but weird symptoms

Só my boyfriend and I last had sex on August 10th. I was on the pill but we didn't use a condom. Around August 22nd I threw up out of nowhere (I never throw up) and I have been feeling cramps, weird discharge and some diahrea. 
I'm not pregnant right? I don't have the courage to go and buy a pregnancy test  😁 also my period is irregular and it's not due in a minimum of 10 days.