Period mid-cycle...

I have been on the mini pill for almost two years now, and I was on antibiotics for the past 10 days for double ear infection/sinus infection. I missed a couple pills while on antibiotics (but not back to back) and my husband and I didn’t use protection. I’ve been bleeding for about 3 days and was wondering if anyone knows why? I have missed pills before, but never had a period mid-cycle. Any advice would be appreciated! It’s during the time when I would normally ovulate. I have mild cramping and a light flow. Thanks!