how do you know if it's a MC

I don't use birth control and have always had regular periods. My SO broke up with me and it broke my heart 
my period came a few days early but it wasn't normal it was light flow and dark blood which is not normal my first day is always heavy for me and really red. Day 2 I was bleeding non stop! Bright red lots of clots major cramps. Day 3 the same as day 2. 
I have a lot of stress in my life and I'm scared that I may have lost a child. No I'm not ready for a kid but the thought still hurts on top of I know MCs run in my family on top of hormone problems leading to MCs.
I just want to know if it could of been a MC I'm on day 4 and still bleeding and not getting lighter this is not normal for me. I've had a lot of stress for 2 years now and my periods are always the same.