FWIW, Dr. Mindy Pelz recommends only fasting during the 3 weeks after the start of your period, and to avoid it the week before your cycle begins. IDK how much stock to put into this piece of advice, but maybe it helps.
I still fast the week before my period bc I don’t find that it affects it. But, maybe using this strategy in the future could help you.
Fasting has a fairly huge impact on your hormones usually because of amped up adrenals. This is one of the reasons it’s recommended women fast differently than men. I make a point to do shorter fasts the week before my period. I know lots of women who have amenorrhea from fasting too intensely
I have hear fasting the week before you menstruate is not great for the production of progesterone, and other hormones that flux at that stage of the cycle. Other than that week fasting should be alright. However, hormones can often be stored in fat cells. So if you are burning the fat you may be releasing sex hormones unknowingly.
Covid is just one example of a lot of coincidental things that could have caused this, chemical pregnancy probably the most common and the least common… idk, ebola? Most of the things on the list are harmless. At a certain point if you’re legit passing 7ml * 12/day * 5 days = 420 ml the amateur midwife in me starts wondering if it’s one of the things that is not harmless, like an ovarian cyst that’s left far more blood bleeding out on the inside and has become a 911 emergency.
https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/management-of-ruptured-ovarian-cyst#:\~:text=Some%20ruptured%20ovarian%20cysts%20can,cases%2C%20this%20can%20cause%20death.