I think Im stressing for nothing?

okay so the last time my boyfriend and I have had sex was 3-4 weeks ago. We had sex twice both times with a condom. I was at that stage when youre still kinda on your period but you arent. Hes positive that the condom didnt break. Ive been really gasy and somewhat light headed. I dont know if im just tweaking for nothing or if im actually pregnant.. HELP