I find that when I sleep after day 1 I just sink into my mattress and fall into a deep dreamless sleep, and don’t even sense the time passing. Then I feel surprised that it’s morning already, and when I get up, my only thought is “I rise”.
i never had issue sleeping. I think if you are doing extended fast you will feel cold hands/feet even in bed. It will take a little to get used to and you may rub your hands together to get warmth but its a natural result.
Oh no. If it is something that gets messed up when I fast it is my sleep. I sleep more lightly, have more dreams (not nice dream) and I remember last summer when I jumped into fasting how I dreamt that I ate and broke my fast.