I just started my second pack of birth control pill after a few month break from the first pack.

I didn’t have any side effects for the first pack, but this time I started bleeding right on the second day of the pill. At first I thought it’s a period, but it’s 8 days earlier than my period, and this is the 7th day, and I’m still bleeding...

How to tell if it’s period or a breakthrough bleeding??? Also if it’s period, will the pill prolong my period????