Scared to go to the bathroom

Hey there. I need some advice. Today I was one day late on getting my AF. This morning I tested and got a bfn. I have lots of cramping like AF is pounding on my door. I am scared to go to the bathroom, afraid AF will show ip. I know it's silly. Could I still be pregnant? I don't have a lot of symptoms. My breasts are bigger and sore, my back hurts a little and today I was dizzy. Not nauseous or anything. When should I test again? Does anyone else have the same fear and how do you deal with it? Thanks for advice