Just had my wisdom teeth extracted and I am feeling extreme depression?

I just had all 4 of my wisdom teeth extracted on may 6th. i was on 4 valium and then nitrous gas to have the procedure done. after wards, i was on lots of vicodin for the pain and then valium because the vicodin makes me EXTREMLY cranky. It's still a few days later and I am still feeling depressed. I've never experienced something like this so I'm just wondering if this is common and when it will go away