It wouldn't surprise me at all learn of a link between Abnormal periods and ME, my periods always worsen my overall symptoms. I used to get so ghastly pale, weak and exhausted that my doctors were always visibly amazed that I wasn't anaemic. I've only had anaemia once following surgery and that was only found when the doctor examined me and ran some extra tests because the post op bruising I had on my stomach wasn't healing weeks and weeks on and I was a lot worse and declining.
What is funny is that thinking about it, despite the crash I had initially and the worsening of all symptoms, sometime after I'd had this surgery and my Endo had been minimised as much as possible by being cut away, I had a spell when I was the best I had been since I totally collapsed and was severely ill. I think because I didn't properly understand about pacing at the time I over did it and had another crash, but I wonder if I had this spell of being a lot better (for me) because I'd been forced to sit more still due to having abdominal surgery, I tend to wriggle around a lot in bed due to pain, risk of pressure sores etc. Or whether having minimised the Endo it gave less for my immune system to do and meant my body could start to 'heal'. Obviously I have no real way of knowing but I do wonder.
I'd forgotten about that 'good' spell because the 'bad' immediately after, and later, was so, so bad. But I definitely had a patch, quite unexpected several months on from the surgery when I was managing to do things like get myself in the shower, wash myself, dress myself and get back to bed and at the time not having mega payback for doing it like I would right now. Not every day of the week but once a week or so. For me that's huge!