Ipod touch 3rd gen wifi is evil!

So i JUST got a 3rd gen ipod touch and the wifi worked fine and wonderful for the first week. i Just went to school today and tried the wifi there and it didn't work but i tdidn't think anything about it. now it won't work with my home wifi either. when i look at the settings bit for my home wifi sometimes it gives me information like the IP adress, subnet mask, router, DSN etc etc. and sometimes it dosn't. one thing i noticed is when it DOES give me the information the search domain comes up as the one for my school. which is weird because im not at school. and i don't know why thats there or how to change that. It ways that it has connected to the network but the wifi signal that usualy pops up at the top isn't there. it would be lonely to find some help for this!