Pregnancy scare

Hi ladies so I just recently became sexually active with my boyfriend and on the thirteenth of July we had unprotected sex, and I had just gotten off my period he pulled out a minute or so before and then came on my stomach, but I'm worried I might be pregnant, I'm not late on my period or anything but I'm just worried cause I read you can get pregnant from pre cum, I've taken multiple pregnancy tests and all of them are negative, is it safe to say that I'm not pregnant or do I keep checking until I get my period?? Help!