Concerned

Hey all.

I’m getting slightly concerned with my current cycle.. I’ve done some research and still haven’t gotten an answer to my questions. My period is pretty irregular, and I don’t take any birth control at the moment. I am sexually active, and we sometimes don’t use a condom. Right now I’m three days in, and I’m experiencing a significant amount of blood, the heaviest I’ve had ever in my cycles. (TMI) but I go through a super tampon in an hour or two. This doesn’t seem normal for me, and I’m worried that I might be experiencing an early miscarriage, but I dont know if I was pregnant or not. Before my bleeding started, I was experiencing awful nausea and abdominal/pelvic pain as well as being feverish and physically drained. Could this just be an abnormal cycle for me, or should I be concerned about the possibility of a miscarriage?