Should I get a blood test to be sure

So I had sex on the 28th of January and I was on birth control but also taking antibiotics so my mom believes I may be pregnant because my dumb self let the guy cum ON my butt (which he had already taken the condom off before I said yes but of course I could have still said no). Well my doctor knew I was on it cause she asked and she didn’t say anything to me. I also contacted the planned parenthood hotline and they said only one form of antibiotic had been proven to effect it. And it wasn’t the one that I have taken. I stopped taking them a week before I had sex. And that week I had a period. Well I still haven’t gotten my period and I’m on lo loestrine fe and I don’t always get a full blown period on it sometimes not even one at all. I have taken test. Exactly three weeks to the day that I had sex like I was advised and took some 5 days earlier test and they were all negative but I know ppl get negatives all the time and then still end up pregnant or har I tested enough?? Someone please give your advice cause this experience had made me realize I am not ready to be doing adult things even tho I am sn adult.