Dude, first of all congratulate yourself for making the choice to pick the better version of yourself. Your choices are between what feels good right now and what is most important. This is a journey and you must allow yourself the time to transition to the better self. Stop beating up yourself you can do and realize that this is a new set of skills you much acquire, that you are going to learn a brand new behavior and transform to this new state. I share what worked for me.
1. Do not drink alone. Just make this rule. No sitting at home and putting away a 12-pack. You seem to be ok for weeks. So challenge yourself to a 3-week limit, put it on your calendar. Pick a nice, upscale bar, dress up and treat yourself.
2. Start waking up early. For extra credit before sunrise. Get out of bed. Go for a walk in the chill of the morning. Feel that air in your lungs. Just do this.
3. Loose the friends. This is the hard one. They are not your friends. You help them feel secure in their lack of agency over their lives. Just very very slowly start being less available. And here is the opportunity to gauge who is a good friend - "I am making a change, lets meet for a walk/movie/museum instead of the bar". The ones who berate this path, loose them.
4. Of the few people remaining from step #3. Appoint someone as overwatch. There will be a time you will be like "fuck it" and get yourself a bottle of wine, 12-pack or whatever. Call or text this person for overwatch request. Take a video of you pouring the booze down the sink. And send it.
5. Finally, remember what Tony Stark said to Peter Parker -- if you are nothing without the suit, then you shouldn't have it.
Epilogue: Guilt. This is the worst thing. All our learning is based on institutional guilt. Tests. Grades. Evaluations. Re-imagine yourself as in third person. Your body is a resource. And you are equipping it. Guilt is rear view mirror stuff and a poor motivator.
What will happen with you is this. You will fall in love with early mornings. You will have time in the morning to do something you truly endear. You will trust yourself with this block of time and this capacity will overflow into all aspects of your life. And in about 6 months' time, you will dress up, you will go to the nice bar, order that drink and very very likely just walk away from it.
Good luck and godspeed.