What Causes An Altered Sense Of Taste?

I am 37 year old female and just after Christmas I began having a horrible taste when I eat or drink anything. I had previously had a cold/sinus issue and really thought that had messed with my sense of taste so I waited it out. We are now creeping up on a whole month of my food and drinks tasting like I have poured aspirin over it. What could be causing this? What can I do to gain my taste back again?