plan b bleeding

I took plan b about 8 days ago when my bfs failed to pull out. Took it 6 hours after and it was about 2-3 days before ovulation. I had no side effects but on the 5 day afterwards I got period cramps and bleeding like the start of a period. Same the next day but there was a little more blood than the day before and then today still some. It had tiny blood cLots sometimes. It's been a consistent amount of bleeding. Period isn't due until a week and a half from now so what is this? Is this a side effect? Or is this a suuuuper light period? When can I expect it to stop?