Am I pregnant?

Y’all I just had sex yesterday. I’m about to be 18. The guy had a condom on but it hanging off his tip some, but it was tight around him. I know he should of got a right size condom for himself. But I mean is there any way I could get pregnant from it. I’m really stressed, it’s been on my mind all day. Idk what’d I do. Idk if it’s to early to take a test or what. I just need help. I can’t be pregnant rn. My stomachs been hurting today. Idk if it’s because it’s been on my mind or what and the stress. I had diarrhea earlier today. Idk if that’s the case. Y’all please help me.