Super long period. Help!!

So this is now day 12 of my period and it’s always been at the very most 7 days. It also came 10 days earlier than expected. Should I be worried? I also had to take plan B in the past month bc of a condom break. It only happened once but it’s possible it did another time too. Is it plan B that’s messing up my cycle, is it just a long period, is it an early miscarriage, or is it actually something serious? Help!