I Drink Around 6-7 Litres Of Water Everyday. This Causes

I drink around 6-7 litres of water everyday. This causes me to urinate frequently, almost once every hour. I tried to reduce my water intake, but it is hard. I feel thirsty, and feel like I'm dehydrating . I've done urine test and blood test and everything is normal. What's wrong with me and how can I reduce my water intake without feeling like I'm going to dry up. I've read about polydipsia. Did I also have this mental illness? Do I need medication?