Pregnant or nah? Not sure what's going on.

So almost a month ago me and my boyfriend had unprotected sex and it was in water, a first for the both of us and it felt so different to us, the thing is we aren't sure if he came inside me, the whole precum and everything. I know it seems stupid. Well here lately I feel like I have had the symptoms of pregnancy but I guess they could also be period signs, I just never have these things with my period. I have took a pregnancy test and it's negative, but it's still on my mind, I should start my period the 2nd week of a new month, always do and it's the starting of the 2nd week and the app said I should have started yesterday, I'm really nervous. Not sure what to make of it, does anyone have any advice? Am I just over thinking it all?