BFP but still light cramping and spotting

AF is due today. Took a Test 3 days BAF was a BFP, was worried it was a false negative. (I know it's rare) 2 days BAF 1 test in the AM positive, PM test positive. 1 day BAF had light cramps and slightly pink cm. I keep thinking chemical pregnancy. AF due today. I took another test this morning still positive.  Anyone know why I'm still having cramping and slight pink cm?? Help please.