I too have this problem from time to time. I have tried several supplements thinking that I might not be taking or eating enough of something. I have heard it said that most individuals are low or depleated of Magneaium. When I wake up with calf/toe cramps I take 2 calcium, 2 potassium and 1 magnesium supplement. Within 10 minutes or so I am able to fall back to sleep.
It’s usually very warm in South Florida. I find that when we have a cold snap – I am more prone to these cramp. Hope this helps.