Talk to General Physician on Laziness, Lack Of Concentration

Hi! I'm 21 years old but I feel like I'm way older than my age, my laziness is on it's peek. I can't overcome it. I tried to improve my self many times but I can't. I'm University student and I fails in every subject due to laziness and lack of concentration. I cannot concentrate on my studies even I tried alot but I can't, I see my family members who are achieving things through hardwork and dedication. I also wanted to do hard work but I can't due to laziness. All I do ever time is sleeping. I smoke also. Should I quit smoking? Even I never do exercise. Please doctors I need your suggestion I wanted to change my life.