Underleved. While it is possible to kill the Gith patrol with very cheesy tactics or with a little luck with a lvl 4 party (or even lvl 3), it's best to fight them with lvl 5. You missed some xp.I got to lvl 5 without even putting a foot into the underdark and before I finally cleared the outside goblin camp (I always fight the bosses in the temple before I'm clearing the outer area).
You should perhaps look at a playthrough tutorial to get some hints where you could get more xp. It's absolutely possible to fight only lvl 3 and 4 creatures (except the spider matriarch maybe) to get to lvl 5.
