When I go to sleep I usually have to be pretty warm, round the middle of the night I often get hot, then cold again.
So I have a thicker and a thinner (natural) blanket/duvet wrapped around me, which I then swap. I always have cold but need warm feet tho,
the amount of (cotton) socks this summer went up to three, day and night, plus often hot spelt pillows, except the hotter days. Bit of Raynaud.
Sounds like you, RLG? And, similarly, breezes quickly increase the fibro-ache to a max.
Whether or not I have Hashimoto/thyroid isn't clear to me from what my various docs are saying (Sjögren's is being tested)...
Now I've gotten on to short cold showers against the ache, I've realised it helps me sleep too, but also against hot flushes at daytime.