What Causes Heavy Vaginal Bleeding With Clots And Abdominal Pain?

I had sexual relations with a man on the 18th, but we did not have sex. I don t believe that there was a chance that any of his ejaculation got on me, but from these symptoms I am worried. I had my period 2 weeks early (started on friday the 22nd) and was super heavy all day on the 23rd. On the night of the 23rd, I passed two rather large clots. I put them in water and they both dissolved down to white, tendon/tissue looking masses. I ve had somewhat of a medium to heavy flow today (the 24th) and I ve had stomach/groin pain for the last 3 days- it feels like a deep, blunt pinch. Is there any possibility i was pregnant and miscarried?