Weird cramping

My period is due today I haven't started yet but I had a BM and I was in pain afterwards I've been a bit backed up as well I thought it was my period starting but nothing yet currently trying for baby number 2 thing I find strange is that it wasn't like normal period cramps it was like I pulled a muscle in my tummy going to test in couple days if my period doesn't show up but has this happened to anyone else