This never happened before. Please help

This was my first cycle using metformin in conjunction with my letrozole. My period was 5 days this cycle instead of my normal 7 days and it was also lighter for some reason. Well I started testing cd 11 (yesterday) and got a flashy smiley on my digital advanced opk. I started spotting throughout the day (only when i wiped) and had very light mild cramping. Well today cd 12 I woke up to a flow of rust colored blood and mild cramping (like a period). The flow is light like my last period but idk why this is happening. Am I not going to ovulate this cycle?