Why cant i stop laughing hysterically?

whenever i start laughing, i literally cant stop laughing for hours! straight! IM NOT EVEN KIDDING! my mom made me run around the block cuz i couldnt stop laughing and its nighttime and i am stil laughing! LOUD! AND HIGH PITCHED! I DONT EVEN KNOW WHAT IM LAUGHING AT! WHY AM I LAUGHING!???? HAHAHAH