Everyone gets ill when mixing with a new bunch of people. It'll be like that for your first year at least.
The most amaaazing cold treatment I've ever had is Contac 3000 (it even sounds like it's from the future). When I was a vocalist in a band and I had a cold I took them and they make you feel human again - not perfect, but definitely better than all other apparent "Cold & Flu" treatments. They're slow release and don't make you drowsy or anything.
Simple paracetamol worked wonders for me when I was ill during freshers. If you're feeling REALLY rough, don't push yourself to go out drinking or anything - you'll miss one night of fun but you'll feel so much better the next day.
You could try vicks first defence, if you start taking it today your cold may not be as bad and could even go away. Failing that defo lots of vit C and also try zinc or ecinacea(sorry thats probabaly spelt wrong). Hope you feel better soon.