Help😖😖😖😫😫😫

So recently I’ve been having sex with my partner using the pullout method. It’s been working and we haven’t had any issue but my period is over a week late I took an at home pregnancy test and it came negative then I went to a free clinic and the same thing happened, it was negative. My period still is here and I’m starting to worry. Could the tests be wrong or is it just my body acting up? I know stress can delay your period but I don’t know what to do. I just want to know what is going on.