How do you know when you're on an emotional high, and when you're on a low?

Are there ever times when you don't even know what you're feeling, but then something familiar tells you what road you're suddenly headed down?

Personally, when I'm suddenly tired all the time and have no appetite it's a sure sign that a bout of depression is coming. (Also when I can't listen to the radio). But when I find myself wanting to make people laugh (in the office, at home, online) and start snacking (especially sweets) or BLASTING the radio in the car, it's a sign that I'm on a high point & things are good.

What about you?

[Edited 9/11/12 14:16pm]

My moods change with the breeze - whether I'm up or down, it never lasts long.

That all changed within the last year - my hormones got alllllll screwed up. For a couple weeks before last Christmas (when everything sort of took a dive), I was in a state where I was actually fantasizing about driving into the path of an oncoming semi. I couldn't think straight and was extremely agitated. (How I managed to get up and go to work in the morning is beyond me.) Thank goodness, I had about 10 days off around Christmas and New Year's - and wasn't in any plays at the time. I don't know how I would have done it.

I've spent the last 10 months trying to figure all this out - and I'm finally starting to feel like myself, again. If I spend more than a day feeling down, it means something needs to be adjusted - and I get it handled.