greenish skies on sony hdtv rear projection hdtv

I BOUGHT A SONY KDF42WE655 REAR PROJECTION HDTV ON BEST BUY 7 MONTHS AGO..AT THE FIRST IMAGE WAS AWESOME BUT IN THE LAST 2 MONTHS I HAVE NOTICED WHITES LOOKING YELLOWISH AND SKIIES LOOKS GREENISH ON ALL INPUTS (ANALOG, HDTV, DVD)..I THINK IS TOO EARLY TO THINK ON A NEED TO REPLACE THE LAMP.. IS ANYONE HAVING A SIMILAR PROBLEM OR KNOW ABOUTH THAT?