Peeing a lot is a symptom of things other than pregnancy, so there is no reason to assume it is pregnancy. You can never rely on symptoms when you are wondering if you are pregnant.
Peeing a lot is also a symptom of uti, which it sounds like you were already checked for, and diabetes. Soda , alcohol, caffeine, and some medications can also make people pee a lot more than usual. It can also be a sign of inflammation of the bladder. Since inflammation of the bladder can be difficult to diagnose, your best bet might be to go to a urologist.