Having to pee so much even when you don't drink anything can be caused by an overactive bladder.
Causes of overactive bladder include nerve damage, certain medications, infection, trauma and certain fluids.
Treatment for overactive bladder include medications and nerve stimulation.
Also when you drink less fluids, your urine becomes more concentrated, and the more concentrated your urine is the more irritating it can be to the bladder, which can trigger the sensation that you have to go more often,
Frequent urination is also a common diabetes symptom.
High blood glucose levels in the body result in excess glucose entering your urine, pulling extra water into the urine, and increasing thirst.
Diabetes describes a group of conditions that affect how the body processes blood glucose levels.
If you continue to have to pee or urinate a lot even when not drinking a lot you should see a doctor about it.