Need advice on if preg or no?

Okay out of the blue my mom says "U better not get pregnant" which makes me start getting paranoid about it. Ever since I've been feeling weird and have a stomach ache from it. Also my nipples are slightly sensative. Note i didnt feel ANY of this before my mom said it or me looking up the early signs. I hadnt had sex for over two weeks (june 15th) so I took a p test (June 26th) and it was negative. Then after i told myself to relax and calm down the symptoms pretty much disappeared except i kept pressing on my stomach hard now and then to see if anything was different and now it feels a little weird. I havent had cravings or anything. Whats up with me??