confused as ever

Kam
So my last AF was 2/18 and started out very light spotting, pink/brown discharge to where I was thinking it was IB. Took a test that day and it was neg. I'd go to the bathroom and would only see discharge when I wiped, then eventually would see a bit more as the day went on but only to barely cover the tip of a tampon. So now my ovulation window has passed & had EWCM on 2/28 & 3/1 which is when we also did the BD. He pulled out both times though bc he doesn't think we're financially ready. My ovulation window is over according to the app but yesterday and today I've been cramping/feeling pressure and my boobs/nipples are really sore. I'm also nauseous at times but not enough to vomit. Any insight? Anyone else this happen to and you get a BFP?