Can someone help me?

So I am on metformin to regulate my cycle. I’ve been on it since June after my miscarriage. My cycles were on time July/August. But I am not 4-5 days late on my period. Has anyone else experienced this? I didn’t get my first positive test until 13 days late with my first pregnancy. I have had some brown/pink spotting (very very light) the past few days. Off and on. I’m just confused on what’s going on. Should I call my doctor? They told me it could take a few months for my cycles to regulate the first time I’ve called but I figured since it was regular so far, why is it late again? What should I do?