Anyone else?

My cycle has been really off for about 8 months or so. That being said I'm on cd31, af is supposed to be due next Monday. I took a test 2 days ago, bfn. Last night as i went to bed i had cramps in my left ovary, and just overall felt really crappy. I had also eaten some really bad food, so i just assumed that was why. This morning i still don't feel well, lots of diarrhea (sorry for the tmi) and my abs hurt but I've not worked out lol. Anyone else ever feel like this and get a bfp?