Kriston's right on (as usual
); I don't think it's uncommon to find that you need to keep pushing the envelope in whatever context works for you. I'm writing again, too, because you do need to do something that stretches you; even when I was working, if it was a semester with courses I'd taught lots of times before and I didn't have any research projects on the go, I found I needed something else--I did a lot of crafts, I'd pick sort of weird topics and go find out everything I could about them (Frenchie still laughs about my "cows" semester), or whatever.
I think, too, that it is not rare for an avocation to become a vocation, so maybe if you follow some passions in your off-hours, you might find that they lead you into a new kind of work, too.
Good luck!
minnie
