Ok so, all my life, even since my first period, I've had irregular periods. No idea why. I do know the doctor said one ovary is curled up under its self but nothing is conclusive.

So I've just lived with it. I have no schedule. My period will come whenever it chooses to. Sometimes I skip months, once I had a period that lasted the whole month.

Normally, when I do get my period, its very sticky, and dark, almost brown. Its just what I've been used to my whole life.

But today and yesterday, I've been on my period (at least I think so) but its been bright red, free flowing blood. Not the clotty, sticky brownish blood that I have always seen.
*edit part* And it is HEAVY! I forgot to mention that. It's the heaviest period I have ever had.

Ive also been cramping, which is new for me. And hot flashes every night, which is new. And constipated. Which I've also never really experienced with a period.

Could I have miscarried an early pregnancy? Or could it be something else?

Aside from the usual question, like assuming you are sexually active. You have never suggested you have a partner, but are a single mom; you have been experiencing an altered lifestyle because you are trying to lose weight. Change in diet and routine, exercise, etc. would be enough to alter your menstrual flow.

If you think it could be an early miscarriage, then possibly, can't say my dear without you seeing your doctor and explaining the symptoms.