I used to drink a lot of diet soda. I went to a counselor to help with my anxiety and one of the first things she asked me was how much water I drank. Your body needs water as it is made up of about 60% water and that needs replenishing. Soda, coffee, tea will make you lose water. She asked me to drink a large glass of water with every meal and I got into that habit. Made a difference, lessened my anxiety and helped me think cleaner.
I still drink some soda and coffee , just a whole lot less. Don't do a lot of juice as its high in calories.