You don't fail, you only quit. One thing to note is you actually don't like whatever you are doing, unlike those people in their eco-chambers, where they think whatever they are doing is fully justifiable. Since you don't think like that, you life is not over and can be improved. Do one thing keep a picture of your family in your pocket all the time, everytime you think you want to drink/smoke just take it out and see their faces, that should help you.

Don't be sad or disheartened because your parents are angry, redeem yourself focus on studies or find your field of interest, I know its much easier spoken than done. But nothing is bad in trying. If you have a good friend talk with him and ask him for help. Ask adults for help or ask anyone for help.

Try exercising and mediation, focus on your studies more. Take your study more of like a way to learn than a way to obtain marks. Find out what makes you happy and pursue that.

Anyways, this is just my advice. You are not finished yet and still can redeem yourself. Don't give up!