I was water deprived. All of the coffee and iced tea I was drinking was not enough to hydrate me. They both have caffeine and serve as a kind of diuretic. Now that I am older, a senior, I need to be careful about that.
I immediately drank 4 glasses of water and continued to drink water all day instead of my tea. I gradually felt better as I became hydrated. I now make sure that the first thing I drink in the morning is a big glass of water, and late afternoon I drink another.
I am telling you about this so you can keep yourself from becoming this way. It is easy to forget when you get older to drink water. We have special things we drink, but unless they are caffeine free and mostly water, we can get in trouble. I am "living" proof.