Is my optical mouse possibly dying?

[Rapture]

If you have spare computers around, you can try switching them between them to see if the OS is the problem. (unlikely)

Most of the time it's just the mouse...

Have you tried clicking in certain areas of the mouse? I've had some that don't work very well if you click near the front after a year of usage. If I click near the base (closer to the palm) it works fine.