Good luck man, you'll be fine. I had a deviated septum fixed and a cosmetic rhinoplasty(nose job) at the same time and it really wasn't bad at all. The pain(to me, at least) was pretty tolerable. I only had to take the Vicodin I was prescribed one time.
The worst part was the stuff they pack inside your nose. I had to keep it in there for 5 days after the surgery which meant I had to deal with the hell of breathing out of my mouth for five days straight. Not only that, but after they took the packing out, the inside of my nose was so raw that it felt like someone was holding a lighter inside my nostril every time I breathed in.
As for recovery, your nose isn't going to look straight at first. You'll have to give at least 6 months for the swelling to go down before you start noticing any cosmetic changes, so don't panic about that. What you will notice pretty much right after you get the packing taken out is how much better you can breathe out of your nostril that the deviated septum was affecting. There's also gonna be a big red scar that sticks out on your columella for at least a year until it starts to fade.
That's kind of odd that you have to spend the night at the hospital though. My surgery lasted 4 hours and I got to go home a half hour after I woke up(someone was driving me obviously).
