Help, need opinions

I am now 16 dpo. Seemed to be missed AF at 14dpo. I've had faint positives with fmu for the past 4-5 days before missed AF. Haven't tested again since.  This afternoon I had a quick sharp cramp like pain followed by pinkish spotting. No blood when I pee but when I wipe and on a panty liner. Seems to be getting a little darker but now heavy like AF when she starts.. Any opinions? Is this a chemical? Or AF just coming late or could I be pregnant and just spotting? I'm so lost and upset