Can you be extroverted in some situations when you’re typically introverted?

So here’s a strange thing I noticed last weekend:

I had no spoons.  I had imaginary freaking spoons.

But I went out to a discussion group about dating etiquette, and that was great, because it was really kind of academic, and not personal.

But then I was able to be an emotional support for other people, and that gave me energy.  Not in a vampire kind of way, but as if I’m only extroverted (and therefore feeling energized) when I’m helping other people.

Anyone else feel something like this?