I REALLY need some help!!

Soooo i had “protected” sex with a guy last Friday and i say protected loosely because, we were both intoxicated, however, i was aware enough to watch him “secretly” rip the tip of the condom and try for another before i stopped him and just wacked him off before going home. I saw him ejaculate on my hands and i know pre cum didn’t touch me at all, however, I’ve been gassy with slight cramps/soreness and today I’ve noticed my head hurting along with some slight dizziness. I’m young and scared and i can’t afford to be pregnant but i think i might be even though i know i did everything right. Am i overreacting or should i really start getting prepared for this mistake?