You refer to it as 'self-destruct' mode so you clearly have some idea of the dangers involved, and your friends are right to be concerned. Many of us turn to a drink or cigarette when we are feeling stressed or down. But it's rarely very constructive. You simply block the problems out rather than working your way through them, which is the only way to move on and put them behind you. So your problems continue to hang over you, and other problems appear as a result of substance abuse, and this can all spiral out of control because your troubles have not been dealt with.
Most people think they can handle it - but very few can, and most do head fast for self destruct.
Do something more useful for yourself At least you have recognised the risks by talking about your problem. Loud rock music, hypnotherapy, immersing yourself in sport or even art . . . When you're ready, confront your problems. Only do this when you feel comfortable and have the support and advice of friends, family or professionals. A good starting point is to find someone you feel you can trust and talk to them.