If you want to implement change in your life, it's a lot easier to tell yourself that you are the kind of person who does or doesn't do a particular thing. It's hard and unsustainable to will-power your way into change. Usually the only change that lasts are the kind that change the person. So start there to begin with.
When you're sitting at the bar and thinking, "I can't drink. I shouldn't drink." you are simply defining yourself by the things you want to refrain from. The things that might bring you shame. Instead, empower yourself and tell yourself you are a kind of person who simply doesn't drink. I don't know what that story might be for you, we all have different stories. But I think stories are the biggest factor and vehicle to change.
So quit investing -- or throwing time and energy -- ontop of the heaping pile of burning trash that is your current and past self. You are not where you want to be and that's okay. Don't listen to your friends and family who tell you you're perfect the way you are. They aren't telling you this with your best long-term interests in mind. They're simply telling you this to fulfill their own story of being your loved-one. Instead, start telling yourself a story of yourself that you want to be.