Endless, I think you realize where you went wrong. Don't beat yourself up over drinking, learn from your mistake.
You can only control you and your actions. You have to decide not to drink, no matter the situation or circumstance. You've got to be strong enough to take a stand, know what you want and if that's to be sober, then stick to it.
If you have a gut feeling you won't be able to stick to your plan in a certain environment, then by all means, avoid that environment.
IMO, you've got to give yourself the best chance at success. In the beginning, I had to avoid any situation that would trigger me to drink. Although every waking moment was a trigger, some venues were more persuasive triggers.
If sobriety is something you really want, be smart about the environment you choose to associate yourself with. You're only hurting yourself when you take that drink.
Good job on coming here and posting. Stay strong and be good to yourself today. One day at a time.