I need advice to help quit smoking weed?

ive been smoking weed here and there since 8th grade. most recentlt being the past 3 years ive been smoking like a chimney everyday. no lie i smoke no less than 6 blunts a day, since then. Im only 21, i want to quit and have tried many times, but i just cant, ive even gotten a pom and that still didnt stop me. ive failed every semester of college and i have this one last try or i get kicked out of UH. i want it i just cant do it. any recomendations to help quit? am i going to feel any withdrawals? my lungs have had like a weird feeling everytime i breate lately, should this be somthing to watch on?