May be Pregnant But Not Sure

Rebecca

We've been TTC for almost 2 years. I have PCOS. I've had regular 30-32 day cycles for over a year thanks to vitamin D and Metformin 1700mg/day. My period is 5 days late and I'm on cd37 today. Negative pregnancy test 6 days ago so nervous to test again. What do you think? Could this be it? Or could my body be rejecting the metformin? Does that happen?