period or pregnant?

So about 3-4 weeks ago my boyfriend and i had an incident and the condom broke. We immediately got plan b and i took it. i got my period 6 days later (i’m pretty sure from the plan b but my period is VERY irregular) it’s now been 11 days since that period has stopped and i started getting really bad cramps and brown/ reddish discharge has been going on for a day or two. My cramps are really bad the discharge is mostly when i wipe but i’m wearing a pad. do you think it’s my period or implantation bleeding? i’m really scared