I get bad insomnia after a big day and crash the next in a stunned daze.
I have also noticed bad insomnia/sleep when sinuses are playing up which i think is from head and facial pain. Usually wake up earlier than normal with a bad headache but it takes awhile to roll out of bed due to exhaustion . I think lying down all night doesn't allow sinuses to drain properly, causing congestion and pain.
I remember early on in cfs days, i noticed a cycle where i would have painful glands in my neck, general aches and pains all the time for several days and at night trying to sleep was really hard due to bad pains in my lower legs , almost like having shin splints.
This would last several days. I would then go into a coma type sleep for 3 to 4 days where i would only get up to shower, toilet and eat then back to bed . I actually slept really well and had no pain during this period and sort of liked it as it was a respite from the insomnia and pain but i would feel guilty as i was doing nothing and not being the husband and father i wanted to be .
I would then slowly recover to 90 to 95% which would last several weeks and then the cycle would repeat, probably viruses continually reactivating. This happened for a couple of years .
Its weird but we can judge certain things by our sleep. I wish they would study this aspect more in mecfs. Also interesting to see if fixing sleep back to normal ie going through the right sleep stages every night and the right quantity, could reverse many cfs symptoms and functionality . Something current meds dont fully address but better than nothing .