I had unprotected sex, and I took Plan B the next day. Within 3 days I had bleeding like a period. My period is around 8-9 days late, but a few days ago I took a test, which was negative. What are the chances that I'm pregnant? I have also been late before in the past.
I would say wait a few days and try to test again. Plan B is pretty reliable, that, along with the fact that you have a history of being late probably means there is nothing to worry about.