Network/internet problems! HELP!

[Play]

So it goes a little suck like this:

For 3 weeks my network/internet connection is a mess. it keeps throwin off me of the net, my messangers keep disconnectin every 2 minutes and my supposedly 1700kbps network slowed down to 120. I have university internet in the dorm, but my sysop can't do anything about this, so he says anyways. I tried everythin, network monitor, troubleshooter ****, asking around and I came here finally, probably you guys can help.
There is another strange thing. Sometimes it gets me disconnected saying a cable is unlugged. Then when I disable the connection on the control panel and re-enable it, it works again.

Any ideas?