Pregnancy ?

I lost my virginity today . So Im going to keep this short .. I know the whole thing about pre cum and the risks of getting pregnant still .. But Before we had sex I gave him head and Im pretty sure there was pre cum . Then we had sex , no protection but we stopped short because I was scared to keep going and he did not cum . I’m freaking out now because I really don’t want to be pregnant .. At least not right at this moment .. Also my period is irregular and I’m supposed to have it next week . HELP?!?!