RR,
Take a good look at Thxlbx's sentence, " In Feb, you were playing the $2...". That is spot on and I think what you really need to focus on. In fact I'm wondering if that isn't the problem right now. You've been running so good for so long that maybe this bad patch you're going through is being magnified because of it. Going back to look at your wins/losses it looks like you were still running good even as late as 4/15. That's only been a week ago. I'm not the best or most experienced player here by a long shot, but I've played plenty to know that a run of a bad week is nothing. I've fell into the trap many times after a bad run thinking that it's never going to turn around (and as you know I'm going through a small one now), but you know what? It has always turned around.
Now it may seem like silly advice from someone just coming back to UB, but have you thought about changing the venue you play at? I'm only back there a week and I'm already getting a bit frustrated at the lack of payoffs that sets and big hands seem to get there. And at this level I don't believe it's necessarily about how good a player a person is but whether they get paid off nicely for their big hands while avoiding paying the other guy off for his. All the other little subleties of playing good poker, while good knowledge to have, isn't going to help much at this level if you aren't hitting the cards or getting paid off for them when you do. I'm going to give UB a few more weeks myself and if nothing changes then I'll be looking for another change.
Also I don't know how often you take breaks from playing, but if poker becomes too frustrating or even a chore (and, again, I've been there myself), take a bit of time away from the computer and come back in a couple days, or even a week or more if needed, refreshed. Your money will still be there. And personally I think it's important to enjoy playing poker if you're playing very often. If you don't then that along with the frustrations of getting bad beat or losing because of a mistake you made can be almost unbearable at times if you don't have fun playing to begin with. This isn't like a job that you hate where you'll get paid no matter what you feel about it. You start to feel that way about poker and you'll end up playing worse and losing more because of it.
Finally, I guess, try not to focus so much on reaching the "next level". If you play your cards right (haha), you'll get there when you get there. Otherwise you're liable to go into a funk each time you lose a bit a see yourself inching further away from that level rather than towards it. You've reached the previous levels so quickly that it's probably even more frustrating now that you are currently moving away rather than towards the next level. But that'll change, just give it some time. Pretty soon you'll probably be running so good again that you'll think it's impossible to hit another losing streak. Of course you will and you'll just have to grind it out until things turn around again.
In summary, keep your chin up, things'll change soon enough.