My meaning of tired

I've been struggling a little bit lately with a feeling that people don't understand what I mean when I say "I'm tired". So I'm going to attempt to explain what it is I feel.

My "awake" time
You know that feeling when you can barely keep your eyes open because you're so tired? Or when you've had a few late nights and get to Sunday afternoon and just have to have that nap?
That's me when I'm "awake". It's not always quite this bad, but at least half of my day is with that feeling.

So if that's me awake...what is my "tired"? This one is a bit harder to describe, but I'll give it a go...

My "tired" time
This is more the feeling you would get if you've pulled an all-niter, had a full day in the office where you've had to sit through numerous meetings and remember a whole list of facts and figures, then gone and run a marathon. Your body aches, your mind is mush, you can't process anything that is going on around you, you feel dizzy and downright exhausted. You get so anxious that if you don't go to sleep right now you're pretty sure you'll start to cry.
This is me when I'm tired. This usually hits me at about 9pm.

So if I say I'm tired, or if I bail early on a party (if I get to it at all), or if I suddenly shut off halfway through a rehearsal or dinner...this is why. This is how I feel.