A little concerned and confused

Ita ♡♡ • 28 and TTC #1
So my period is always on tim. on Wednesday I had a bfp. I was 6 days late. At 8 days late I started spotting. So I just assume Af is here. But this has been the weirdest Af ever. So I have bad cramps but the bleeding is super light. It doesn't even hit my pantiliner. Only see blood when I wipe. I'm going to call my dr. Tomorrow. But has anyone had this happened? If so what was it?