30 days is no joke! You should be proud of yourself for having done that alcohol free time. I am sorry that you had a relapse and the evening you had. The good thing is that you are here looking for support and sounds like you are done with the drinking lifestyle.
This is a wonderful community filled with support. Make this your day 
I find the Checking in daily to maintain focus #60 and the Daily Gratitude, The Air Of Recovery #5 threads really help me on the sober journey.
We are all here working through our addictions and helping each other out. I do hope you keep active with us here 