I think I am developing a sinus infection. I've had all the symptoms. I had yellow mucus this morning, one side of my nose is conjested with occasional discharge while the other is normal to runny. This afternoon I blew my nose and there was a small green hint, mostly clear but just a tad bit of greenish color. But now I'm noticing when I blow my nose I'll occasionally see two strands of greyish-blue mucus? What could this be? Is this normal?