bitter taste, change in appetite

prior to being diagnosed with breast cancer in may 2007, my appetite changed drastically, i only wanted to eat sweet things, as a very bitter taste in my mouth was present all of a sudden. at that time i lost about 15 pounds. about 3 - 4 days ago, these strange occurences started again??? is there anything that might cause this bitter taste to be associated with a change somewhere in my body. :confused