Weird cycle!

This is my 5th month on the combo pill.

I take them at the exact same time every night.

My period has been like clockwork since I started them! Period starts on day 2 of the placebo pills and ends on day 2 of the active pills.

This month I’m on day 4 of the active pills after starting a new pack and my period is still going. Not heavy, but not spotting either. Fresh, red blood and I need to wear a pad.

The only thing I’ve done different this month is got my covid shot 2 weeks ago.

Is this most likely why my period is still going? Or could it be something else?

I’m 32 and 10 months postpartum.