I'm A 28 Year Old Female. I Have A 7yr

I'm a 28 year old female. I have a 7yr old son and 3yr old daughter. I receive the depo shots. I have never had a regular menstrual cycle. However, since starting depo I may spot some months but don't usually have an actual period. I've been taking depo for prob a year now. This week has been a stressful week but not any more so than usual. I've started my period about 3 days ago. Day 1 was the normal spotting. Day 2 and 3 (yesterday and today) I have been SOAKING threw my feminine pads. I'm also passing clots. Yesterday they were smaller in size. Prob about dime size. Today though, there are some that are still about dime size but some are also quarter size and even half-dollar size. I'm cramping a great deal. Also, I'm EXTREMELY bloated. I know for a fact I'm not prego as I am not sexually active and haven't been in since I was about 3 months pregnant with my daughter (she now 3 years old).
I don't know if this is normal or something I should be concerned with.