Your natural skepticism? You mean doubt in your ability to succeed? Your disbelief that you can do this? Doubt that quitting drinking can really be as simple as not drinking? Your lack confidence that you will be able to stick to it?
This is AV. Set those thoughts and others like them aside, and instead know that you can do this, and that you shall do it. Know you deserve it. Your addiction is struggling, and nagging and whining. Too bad for it. No matter what it says, how you feel, you can do this.
I understand that I can drink, or I can have the life I want, but I cannot have both. I have decided and made my choice. I won't drink anymore, ever, and I am not ever changing my decision.