How to manage this cold at school?!

I started having symptoms of a cold about 2 days ago. It wasnt that bad at first. I am now at school and i can BARELY breath hrough my nose. I took some cold&allergy medicine this morning but it seems to not be helping. I'm drinking water too, because breathing through my mouth is making it become very dry.

My symptoms include
*runny nose
*sore throat
*stuffy nose
*headache
*dizzy spells <---i get that a lot, common for me when i get sick.

**Is there anything I can do, right now to help!! This is making me miserable at school.
***Also is there any other medicne you reccomend, bcus this is not working.

Thanks in advance!