No offence to anyone who has posted and i think all the advice has been well thought through and helpful. But perhaps over and above the advice already given you should perhaps go and see someone, a professional. There is no shame in it, they will be able to tell you what is right to fit your personality. Different things work for different people. As an example, my father has a tendency to take to things easily ie. drinking, gambling etc. Any addictive activity will draw him in, luckily he has the self control to know his limits and stuff but there have been times when it has got the better of him. This contrasts to my personality. I like drinking, but i could go without. I like gambling, but i could go without. I don't smoke so i wouldn;t know. This just shows how things can effect people in different ways.

If you get some one-on-one advice i am sure it could be helpful.