I haven't met anyone who didn't get the jitters, I know I sure did. You are 15 days pre-op, my surgeon had me lay off of any pain meds, booz, cigars, etc about 10 days out, so I suspect a little libation this far from surgery isn't going to make a world of difference.
On a related note, I kicked the cigar habit. :shk: I stopped 10 days before and didn't try another until I was about 3 1/2 months post-op. Just didn't taste right. I tried again about two weeks ago and got the same effect. So I gave my humidor and my remaining stash to a friend who stills smokes em...
I use to drink coffee in the morning and caffinated sodas all afternoon. Now I have one cup of java in the morning, maybe one soda at lunch. The rest of the time its water or fruit juice.
Think about all the good changes you can make as part of this process.