Period came very early and won’t stop!

My period is always regular; it comes on or before the day I expect it, every month, 27/28 day cycles, and it lasts 3 days, max. Always. Except this month, what I believe to be my period came 11 days early. It was super heavy the first couple of days, now just light bleeding for the last few days, total of 5 days so far and not stopping yet.

I don’t have Fallopian tubes which means spontaneous pregnancy (I.e without medical intervention like IVF) should be impossible, so I don’t think it could be a miscarriage or anything like that. I am in a committed, monogamous relationship and we have sex regularly. We’ve both been tested for STIs and are clean, so that’s not on my radar either.

I’m just a little worried and would like to hear if something like this happened to you, what did it end up being? Just a weird, early period that I shouldn’t be worried about? Hopefully?

By the way, not looking for a diagnosis or anything obviously, I know none of us are doctors; just looking for some others’ stories or ideas. I’ll go see my gyno if it continues.