Your body always gets rid of excess sugar through the urine. Diabetics will urinate a lot like every 1-2 hours as your kidneys attempt to cleanse your system. You also feel like your mouth is dry/thirsty. That is because of your kidneys dehydrating you as you urinate a lot. High sugar will cause blurry vision, fatigue, feel hungry a lot even though you ate, sores that take a long time to heal, and tingling pain in the hands and feet. You might feel some or all of them. The easiest way is a blood test to know for sure.
The only way to detect excess protein in the urine is with testing.