Maybe I’m pregnant

What’s the chance of me being pregnant ? My boyfriend and I had sex a day before my period then while I was on my period . He is convinced I’m pregnant. I took two pregnancy tests and I think one was too early then I took another one at 18 days . Is that still too early ? I feel like I’m pregnant and my boyfriend said he prayed and God told him I’m pregnant . Help guys idk what to do. We arnt trying to get pregnant but if it happens we will be okay with it. What is the best pregnancy tests to use ?