Up and down, like a seesaw

The swings of playing three $50 NL cash games a night for months now is starting to wear me down, and I'm not sure how to fix it.
I just finished Harrington's "No Limit Cash Games Vol. I," and it's improved me, even if I don't agree with some of his advice and some of the advice is just obvious.
I'm winning more than ever.
The problem is, I'm also losing more than ever.
This is proof to me that I'm no longer the nitty player you all think I am. I'll gladly take that (still well-deserved) reputation, as it helps me steal blinds. But it's no longer completely true. In fact, after reading the book, I realize I was making some pretty stupid bets. I was being too aggressive, in other words.
I'll wait for you to finish laughing before I continue.
Still with me? OK. In the last three months, I've plumped up my bankroll, and that's because I've won and also taken advantage of Bodog's reload bonus. But the swings have been pretty wild. I might lose a buy-in or more when I lose, and when I win, I might win a couple.
Most of the losses, lately, have been coolers. I hesitate to say this because to me the term "cooler" is abused and overused. When your J-J loses to A-A after you've called an all-in post-flop and your stack was deep, that is not a cooler. When your straight loses to a paired board and you shove on the river, that is not a cooler. When you stack off with top pair, I don't care what happens, that is not a cooler. Those are bad plays. Period.
But lately I've lost my stack with a K-high flush (only three on the board) to an A-high flush, twice I've been setted over setted (yes, I had the smallest set possible) and I've lost pre-flop with K-K when it's run into A-A four times.
I dunno. Maybe those aren't coolers either.
I've also made some bad plays. I jammed with Q-Q on a low board when the other player was showing strength and of course he had a set. That was incredibly dumb in a cash game.
As I play in the final Bodog WSOP series tournament tonight, a tournament riddled with my mistakes, mistakes that cost me a seat in the freeroll, I'm wondering how to keep winning but keeping the losses down.
Any ideas?