What could be causing me to be losing my sense of taste?

Nasal issues often: Most of taste is influenced by sense of smell. Whatever decreases that, e.g. A cold, sinus infection, polyp, etc can affect taste as well. Sometimes effect after head trauma, cranial nerve issues, local problems after e.g. Radiation rx-"mouth blindness", unlikely tumors, etc. See md, check for problems that may be easily rx'd. Specialized care is available in research centers for tough cases.