Internet is REALLY slow

Hey guys, I'm sitting on a lan party, but I have a problem.
My friend next to me just tested his internet speed, and he could download with 90 mb/s.
However, I can only download files with a top of 20 kb/s, even if we download the same file my speed is ridiculously much slower than his.
I can download files from LAN in a second, but displaying images on some sites can take hours.. a guy from the support was here some minutes ago and he tested the network on his notebook and the speed was normal there.
The weird thing is, I can play games (Counter Strike etc) on internet with a very low latency, and no lag at all..

Please help me, this party is only twice a year..