Ok guys I have a huge problem

I don't know if some of you remember that a few months back I had to miss work and I ended up really having to miss because my upper abdomen had been hurting, well, they told me it was gastritis and not to worry

As it turns out it may be gallstones!!! I am totally sh*tting bricks. I have never had an operation and it's the most scary thing for me. I still have to wait about 2 weeks to find out but I am so scared. Has anyone ever had this procedure done? How is it?
I hate the idea of being put to sleep, What if I don't wake up. What about the pain? I am even scared to google on this