Drinking is the equivalent of sitting on the couch doing nothing. Do you think you could go from triathlon to couch potato in a day? No way, you have to work out and get stronger. The same is true for your mental health. You can't just sit back and use drugs and alcohol to take care of your problems, the ONLY way to get better is to work with your problems. It might seem difficult, but every time you do it, EVERY time, you are getting a little bit stronger. It's like your brain is hitting the weight room.
For me, I found motivation to be fleeting and unreliable. At the end of the day, you just have to say no and not pick up. You are not powerless, you do not have a disease, the choice is ALWAYS yours. Go to therapy, learn about yourself and why you have panic attacks and anxiety issues in the first place. There is a cause, and it is entirely within your reach to discover it and work to resolve it. I recently got a book that called feeling good: the new mood therapy, you could read that and give it a try. Also investigate and watch videos by Adyashanti, Eckhart Tolle, Byron Katie, Mooji Ralph Smart (Infinite waters) and Don Miguel Ruiz. All of the above mentioned people have really helpful insights into the nature of life and human experience. These are the kinds of things you should be thinking about right now.