Why is my nose dripping so excessively when i have no allergies?

I started having the effects of a sinus infection last night while still drinking plenty of water. I could tell it was getting worse with every swallow. I woke up this morning with the same sensation. While i was at work, my nose began running so bad, it would be dripping on my desk, hands and clothes because it was so watery and thin. What could be causing the profuse drainage coming from my nose?