Help?

I’ve never been to the gynecologist yet. I’m 18, I’m too scared to go. I’ve had unprotected sex twice. After the first time (beginning of February), I’ve been really scared, and I’m not sure how to tell my mother. I’ve been having pains sometimes in the uterus area. Sometimes my lower back hurts. I’m super afraid, what if I go and i find out I have something? I had sex with my “fwb” yesterday, and he only went in without a condom for not even 2 minutes (he was afraid he was going to cum inside me). I’m probably being stupid, but what if I have something and spread it to my sexual partner? 😔