Miscarriage ?

So about a week and a half ago I experienced really horrible cramps. I don't typically cramp before my period and when I do, they're very mild. But these were the worst I've ever had and they were constant for at least a week. Then while still having these cramps, I started what I assumed was my period, it was a really heavy flow but it only lasted 3 days and my periods usually last about 6 days. I also experienced back pain. I assumed it was just a bad period but I was reading things about miscarriages and those are pretty common signs. I might just be overthinking it but thought I would ask