scary clot or?

I was walking back to my dorm from the store and all the sudden I had this huge rush of blood and something came out of me that was big enough that I felt it and when I looked it looked different than any other clot I've had or anything, my period already came this month and I am very regular, I thought there was a chance that I was pregnant because my last period was very very light and strange and we had a condom accident (but I'm on BC anyway) but when I got my period this month I thought I was in the clear. Could this be a miscarriage or just a really scary clot accompanied by cramping and a lot of bright red blood?