Need advice

I recently started talking to my ex again. I’m 16 and he’s 19. I saw him on Valentine’s Day and we had sex. he invited me over again this weekend. Last night we had sex again, he said he came inside of me a little bit and I’m not on birth control. I was just on my period the other week but I would rather mot wait another month to find out if I’m pregnant. I’m not gonna stress over it because I know it will delay my period more but I’m still kind of worried