2 days late missed period what do you think?

ok serious questions please. im 19 and my cycle is normally 28 days my last one started on june 2nd im never really late me and my boyfriend have been careful about using a condom in the previous months but on June 15 the condom slipped and he came in me then we got drunk a few times after and i don't think we used condoms i don't remember but anyways im 2 days late tired slightly nauseous back cramps and i feel kinda weird in my lower stomach area do you think i should test? wait? what would you do if you were me?