Hey don't worry I've suffered massive clots for years since I got mine. I'm 99% positive I have endometriosis the best thing is go to your doc. You may need some iron pills or if you are low in vitamin d they generally give you a week's course of pills to boost it so if you feel really tired and lethargic etc you could be deficient but it's really common in women to be anyway it doesn't mean you have Endo either. Don't panic if you were seriously ill you would have known by now don't get yourself too worried but definitely see a doctor it may just be some low iron iron or vitamin d stores.
I would talk to your Dr. an out having endometriosis!
Bleeding for a month could be a miscarriage.
see your doctor. clots outside our your period are not normal.