Wow, I would have liked to see your face when it happened the first, the second and certainly the third time.

jD can't know whether you're sleeping or not. A developer of such an extension would need to analyse the signals from electrodes that are placed on your face and head to record your muscle tone, eye movements, and brain waves and then decide whether you're sleeping or not.

I use a tool that reminds me of all sorts of things that I need to do/check on a periodic basis. If you've a regular, daily working/sleeping scheme, then this could help as well.