Is it normal to bleed while taking bc pills for IVF?

Hi-

I am on day 26 of my menstrual cycle.

I started taking bc pills on day 5 and will continue until I start stimming.

I started spotting (very dark brown) yesterday,

and it is becoming more of a period today-but not entirely.

I have some cramping, too.

Is this normal? Should I be concerned? Please advise.

Thanks!! Rebecca