There's a problem with my iPod internet connection... how do i fix it?

So, I was up at my friend's place for a couple weeks and when I came back, I can't connect to the internet on my iTouch. I know it's not a problem with the internet connection itself, because before I left it worked, and it works perfectly fine on all our other devices. Though it's a secure network, my iPod is set up and allowed on--but my iPod doesn't even detect the network! What happened while I was at my friend's place, and how can I fix it!?