Need Advice Please!!!

I took plan B October 6th and 5 days later (2 weeks early for my period) I had a very heavy amount of red colored bleeding with clots that lasted the whole day and required me to use super tampons. The period went away after one day and I haven’t had any symptoms since. My next period is not expected till October 26th but I am still worried about pregnancy. Is it possible I could still be pregnant even though I had a heavy amount of bleeding?