Pregnant or a UTI? please help?

ok so i have a UTI (urinary track infection) im on this 3 day pill to get rid of it, today's my last day and i have been feeling really sick like im going to trow up.i had sex last saturday and my fiance came in me on accident. now i don't if im feeling Morning sickness if im pregnant or its my antibiotics from my UTI? please help me! im really scared!