What's happening

My last cycle was Oct 6 and I'm not due for the next one till Nov 6. Last night my back started killing me and I started have severe pelvic pain followed by adopting that within a few minutes turned into heavy bleeding bright red blood with clots. And it has continued thru. I'm extremely tired and weak feeling. Dizzy and woozy. I don't feel right. What's happening? Is this normal?