Thyroid meds

I was diagnosed with PCOS at 15 and was put on BC. In March, my husband and I decided to start trying for a baby. Periods were on a consistent 28-30 day cycle!! In September, I had to switch doctors and ended up having a consult with a OBGYN that also specializes in fertility. We decided to do some tests because of the PCOS because the new doctor wasn’t convinced I actually had it. Good news- they don’t believe I have it but found some slight thyroid issues. In October, I started a low dose thyroid medication. Blood test came back normal but my period is so off now. Last month 10 days late (which was upsetting to find we weren’t pregnant). This month, so far I’m

3 days late. Does anyone have a similar situation? I was hopeful for everything to be normal once I started these meds but I’m pretty upset that my cycle is out of whack!