I got my BFP on May 23 and ended up having a chemical 5 days later. I kind of could tell something was off because I had awful cramping on and off before I even started bleeding. When I mentioned my symptoms (others included being super gassy, breaking out a lot on one side of my chin [normally, prior to AF, this happens with one pimple, not a whole cluster of them!], and the day before my CP, extremely tender boobs and nipples) to my bestie who has a one year old, she said she never really had cramping besides implantation.