With Gab they felt just like AF cramps. I got to CD30 and no AF (I was a 27/28 day cycler back then) so I did a HPT out of curiousity (cos I was so sure AF was coming) and I got a BFP! Had the cramping for a few weeks still after that.
I feel like AF is on her way again and have been feeling crampy off and on from CD18 (3DPO). I've had a temp drop this morning tho so it may just be AF on her way