Could I be miscarrying?

Megan
Hello all! I need to ask opinions on what to do because I'm really not sure. I had my be plain removed in May after the full 3 years and went on the pill. Now I'm not super great at taking the pill at the exact time everyday but I usually get it within 30 mins. My fiancé and I had sex a couple times at the beginning of July(the 1st and 3rd) and I missed a pill a couple of days after and then this past sunday(August 7th)  I had a period from June 30 to July 10 and then from July 17-20 and this most recent started on August 8th. This one feels different though. It's extremely heavy(filling a super tampon within 2-4 hours and very large chunks of blood) along with severe cramping dizziness and unusually strong emotions(i.e. Sobbing over nothing in the bathroom at work today. I am NOT the crying type whatsoever.) and tender nipples(they're usually tender). Today it seemed like all of a sudden the bleeding slowed down a lot too. Could I have had a miscarriage? Since the bleeding has slowed significantly should I go to the hospital?