Spotting?? Confused.com

Hi ladies was wondering if anybody has been through the same as me.

I have a very very regular cycle of 28days. We have been ttc since may. I got a BFP in June but ended in a miscarriage in July. Exactly 28 days after that I got my first AF. Now I'm currently in my second cycle after mc and 5 days before AF but last night me and my fiancé dtd and I had some light spotting( never spotted before ).

What does this mean? My AF has never been early. I'm so confused and slightly concerned at the same time. Help xxx