Welcome back. You didn't let anyone down with your drinking. We're all stopping drinking for ourselves.
I think most people here know what relapse is like. Best you can do is dust off, get over it and commit to permanent sobriety.
About that cooking with alcohol, I never understood it. But I do avoid all foods that have used any kind of alcohol in the making of them. Unnecessary risks are unnecessary risks. I see all alcohol as a threat to my sobriety. You can do it. And you've already taking a huge step by even posting here. You'll certainly succeed if you just stick to it, no matter what.