I've lost 20 pounds in 8 months with no dietary changes, i've been urinating 5 to 7 liters of urine a day. i have unexplained heart rate of 100bpm.

Concerning symptoms : Your symptoms are very concerning and you should be evaluated by your physician as soon as possible. One common reason for excessive urination in a young patient is diabetes. But you should be evaluated for other possibilities.

You must C MD: Not normal. Many systems dysfunction can cause excessive urination. Rapid heart rate likely from “dehydration “. Tomorrow seek medical attention. Hospital ER ,if can’t see PCP. Go,go,go