How bad is it going to get on a First DWI?

I received my first (and last) DUI 2 days ago. I was by myself and there was no accident or anything like that. Although I still have yet to be convicted of anything, I am still preparing myself for the worst. I have a great job as a design engineer for a large company and I am worried how this will affect my job security. I do little driving for them (it is mostly a desk job), but am worried that they might do a background check upon internal promotions or something like that. Do I have reason to be concerned?