Why am I on tilt if I'm winning?

I'll admit it. If I'd written this post a week ago, it would have been a bit more of a brag.
One month after returning to the online poker world, I'm up $500. But after the roller-coaster it's been, and the amount of money I probably should have made, I'm fairly discouraged.
In lieu of a chart, here's a sentence summary of my bankroll adventures. I was up $400, down $300, up $800, down $600, up $400, and finally down $200 to land at +$500 for the month.
I've had countless periods of re-evaluation during this stretch. I began the month playing a much more aggressive style than I was used to, and I made it work for me. But playing that high-variance style, combined with playing too many tournaments, caused a nosedive. I decided I needed to get back to using the game plan detailed in Collin Moshman's book, Sit 'n Go Strategy, which is essentially solid early, aggressive late. I also decided I needed to play no more than three tourneys per day, so that I valued each buy-in to a greater degree. I was throwing some of them away on reckless plays.
That shift in focus spurred a huge hot streak, and I was up $900 for the month in a huge hurry. I was doing so well, I was actually on pace to turn in a solid score for PokerStars' Battle of the Planets promotion. Basically, the way it works is, you can win some nice cash prizes if you have the best results over a block of 20 sit 'n gos. I needed to complete 11 on a Saturday morning – an obvious deviation from my three-tourneys-per-day regimen. I did not fare well, playing four at a time as I was. I usually only play two at a time, and though I went on a $200 downturn chasing the Battle of the Planets, I wasn't too perturbed. It was a risk worth taking, and the reasons for my struggles were fairly cut and dried.
The thing was, what I thought would be a short stretch of suckitude endured and became an epic $600 downswing. So discouraging. I gave myself a pep talk and briefly righted the ship, but then PokerStars just decided to rape me repeatedly in the luck department. I hate to tell bad beat stories, but here are some of the beats I've taken on the money bubble over the past week:
KK < QQ
AK < AQ
TT < 33
Each of those beats literally took money out of my bankroll, and that's just a sampling. Here's one that happened tonight, on the bubble of a $60 SNG:
-- First, the pre-beat. I'm second in chips with just north of 3,000, when the short stack ships all in on the button. The small blind is the chip leader, and he calls. I fold the big blind. Shorty shows J5o, chip leader shows KJ. Flop comes QTx, giving the chip leader an open-ended straight draw in addition to his dominating hand. Turn is a blank, and the river is a 5. So freaking gross. I relay this hand because my bubble beats are often preceded by a filthy short-stack double.
-- A couple orbits later, I've chipped up slightly to about 3,500. The chip leader has 6,000ish, and the other two have just north of 2,000. With the blinds at 100-200 with a 25 ante, I raise under the gun to 500 holding Qh8h. I'm on a steal. It folds around to the big blind, who calls. The flop comes QT6. He checks, I bet 600. He insta-shoves. I should add at this point, the dude had been playing extremely aggressive, and had authored some monster suckouts in order to have his stack. With about one-third of my stack already invested and a fairly solid read he was on a bluff, I called. He showed Ac6c for bottom pair. Turn was a blank, river was a 6. I would have been a dominating chip leader; instead I'm out the door. So upsetting to be attacked by a donkey like that. Thanks a million, PokerStars.
So that's where it's at. I've actually been playing really well over the past week; it's just a matter of running a little bit better. I've had a few nice moments during the month – a deep run in a multi-table tourney, and a win at a live game at a friend's house. But I feel the month could have been so much more profitable. But that's poker, as they say.
Bankroll: $6,900