Front Seat Head Restraint problems of the 2007 Infiniti M35

My M35 (2007) driver's seat suddenly is "off track". It looks like it's still in the floor tracks, but it has moved about 3 inches to the right to the extent that it now rubs on the center console every time it moves back and forth. There is no longer a gap between the seat and the console, like there is on the passenger seat. What happened, and what do I do? it also moves from side to side and I can move the entire seat by grabbing the headrest. The seat moves when the car is in motion.