How tired are you?

This is how tired I am. I was just reading a new release I wrote and came across the word typed "is". I sat there for what seemed like 5 minutes trying to figure out what I had been trying to say and why on earth I'd use the word (if it even IS a word) I's...and why I didn't capitalize the I in the word.

Then it finally dawned on me...it was simply the word "is". ha Wow...need more sleep.