Is my SSD failing? Can it be saved if so?

Crucial has addressed this issue with firmware updates.

It makes perfect sense that your Crucial m4 SSD has exceeded 5184 hours powered on, which is almost exactly 7 months.

Firmware version 0309 fixes the issue you are having:

Correct a condition where an incorrect response to a SMART counter will cause the m4 drive to become unresponsive after 5184 hours of Power-on time. The drive will recover after a power cycle, however, this failure will repeat once per hour after reaching this point. The condition will allow the end user to successfully update firmware, and poses no risk to user or system data stored on the drive.

Go here to download the new firmware and get instructions for updating.