I had something similar with my last cold. I ended up losing a rediculous amount of weight because nothing tasted good.
For me it got better and passed in a few weeks, but if it gets to the point where you feel like you can't eat much at all I would definitely go see the doc.
I had the exact same systems with my last flu/cold. In fact I get it almsot every time I get a flu/cold. Sometimes when my allergies get bad things taste...salty. I know, wierd. Actually, none of this has happened for a while, but it does all eventually go away.