Whats wrong with me? sore throat...?

I had a cold for 2 to 3 days...i began to feel a lot better...then last night i had the worst sore throat ive ever had. i tried tea with honey, throat drops, ice cubes, gargling water with salt...and it didn't help at all. I have been really congested and having to blow my nose a lot. my head hurts and i'm kind of nauseous....what could this be?