Holding left click no longer works, even after reloadig.

I attempted to break a block, by holding down the left clicker.

The left clicker can no longer be held to break blocks, except in creative, as it only hits the block once, then stops. Switching the function of the mouse buttons in options did not fix the problem, and I was able to use the left click to break blocks in a modded version of minecraft (Technic Pack), so the problem is limited to vanilla minecraft, and is not the result of a broken mouse. Additionally, switching the gamemode from survival to creative and back again, did not resolve the problem, nor did exiting the game, or shutting down and restarting my computer. The bug appears permanent.

Steps to Reproduce:
1. I entered the Nether.
2. I burned to death, and respawned in the overworld.
3. I re-entered the Nether.
4. After a few minutes of gameplay, I attempted to break a block, and found I couldn't.