See the doctor, but this can happen. I don't think it's related to any residual eggs either - in the early days of a young girl's periods and also in the last days of an older woman's periods, the period isn't necessarily associated with ovulation. But you can never be sure, which is why the pregnancy risk is still on the table.
When your periods get really heavy and prolonged (and frequent sometimes) in menopause, the problem is usually hormonal. See a doctor who can do a blood work-up (including checking your iron levels).
I had this problem when menopause started with me - ridiculously heavy periods plus they lasted a fortnight and started up again a week later. My iron levels were dropping fast and I was heading for blood transfusion. Then I was put on HRT and it shut things off like a tap, mid-period. I was on HRT for 18 months then my BiPolar (BP) began to go up, while I was trying to lose weight. So I said, "How about I try going off the HRT, instead of you prescribing blood pressure medications?"
So I went off the HRT, the BiPolar (BP) came down and the heavy periods did not return.
The periods were so heavy I was developing my own comedy routine. "You know you have heavy periods when..." type of jokes. Such as "You know you have heavy periods when you're up to three packs a day and you don't even smoke!" There was one embarrassing day when we went to the theatre with friends. I was changing every 45 minutes (before lunch, during lunch, after lunch, right before the show began), but in the theatre I was stuck for the entire first act. Then by intermission I knew the queue for the loo would be too long and I would not be able to stand discreetly for that time, plus I would miss half the second act while I tidied up. So I sat still and didn't dare move until the show finished. Then I sat there longer, while the theatre cleared enough for me to head right to an empty disabled loo. I knew I would need the sink in the cubicle. And I did. I was as quick as I could be, but I still had security banging on the door telling me to hurry up. Friends standing around waiting, husband trying to stall (he knew what the problem was) while I washed everything, dried it under the hand-dryer then draped my black cape over everything and we headed back to the car. I walked behind everybody in our party, then back at the car husband discreetly sat me on the vinyl sheet we protect the car seats with when we go to the beach. I made sure I was the last one out of that car - that way nobody saw my clothes. And thank goodness for black knitted capes!
The show was great. It had been worth the embarrassment factor - Topol in "Fiddler on the Roof". I wasn't going to miss that! And sitting still, there was no problem. it was only when I had to move...
If it is that bad, you need to see a doctor. And if the doctor won't take you seriously, you need to shake him firmly by the throat until he does.
Marg