Before you go to bed, run a really cool, not quite cold, bath, once in add a bit more cold, then lie there until you have really cooled down, almost shivering, probably for half an hour. Air dry yourself and get into bed with just a sheet over you. This should give you 5-6 hours sleep before you you start getting over heated.
I have done this during the day as well if needed. Yes, I know there is a water shortage, but I consider this a health and wellbeing issue, especially as you get older.
I must say that this year, because the heat is so dry, not humid and muggy, I have fared much better than usual and have yet to need the cold bath treatment.