What Causes Heavy Vaginal Bleeding And Exhaustion?

Question : I have been bleeding everyday just about for the past year, but about every 5 to 7 days I will have, for lack of better verbage, a blowout which is where I have this gush of vaginal blood explode out of me with clots the size of a golf ball and sometimes bigger, it fills the pad Im wearing instantaneous then keeps flowing almost like a faucet was turned on so I have to sit on the toilet a good 20 min and it just pours out then I usually shower, because of course clothing is saturated etc. and it keeps flowing in the shower then I get dressed carefully put on two pads and fill both completely every 30 min for the next 12 hours, then almost completely the bleeding stops and i go another 5 to 7 days with spotting every day until the next flood comes and I never know when it will sometimes it is right after ive had sex and it will start after every time I have an orgasm sometimes Im driving to work I get out of my car stand and all of a sudden its as if my water broke if I were pregnant only it is just bright red blood that gushes out and its a lot not just a few tablespoons its like at least a one cup to one in a half measuring cups worth at that moment then the next twelve hours its a half cup every 30 to 45 min, then it will completely stop. I have no pain with it nothing. help me figure out what might be happening, Im 44 years old I have six daughters my oldest is 25 my youngest is 6 I have a set of twins and I am a twin myself. I have been in my relationship for 9 years exclusively to my common law husband