I would've adviced you to take better care of yourself and fix your sleep schedule but I don't think I'm one talk to about it when I'm the same as you.
Eat an avocado, some green beans with garlic and butter, a steak seasoned with salt and pepper, and drink a big glass of milk and also a glass of water, and you will feel much better if the cause is dehydration. Just water isn't going to help if the necessary nutrients required to retain water aren't present.