I don't know what wrong with me

I've been really stressed out recently like just been getting annoyed with people so easily. Also been feeling sick and tired a lot. As far as I'm concerned I don't think I can have babies because I've had unprotected sex many times and everytime I take a pt it comes up negative, but I last had sex on 21st June, unprotected. Doubt that has anything to do with anything though. Does anyone think they may know what could possibly be wrong?