Plan B Side Effects

I took the Plan B pill on the 1st. I got my period and it was only a few days late so I know I'm not pregnant. However, my period has been almost a week and a half long. My periods are always the average length  (5-7 days). Could a long period be a side effect? I've Google a ton and all I see is short term side effect like nausea and vomiting and long term side effects like heavier or lighter periods, no periods or delayed/early periods.; not longer ones. Please help 😊