False negatives?!?!

Bianca

I had unprotected sex on December 20th after 1 year of being celibate. My period was supposed to come on January 12th but nothing still. At this point I’ve taken 3 home pregnancy tests and I went to a women’s clinic and got tested there. All the tests came back negative but I’m still worried. I’ve heard that sex can have an impact on the woman’s cycle; could that be what’s happening or am I getting false negatives?