Difficulty in the heat of battle

[The Deuce]

I've been playing NL hold em, mainly online but occasionally live, for about two years on and off. For the past year I've studied the game pretty relentlessly, read and re-read many books, and spent a lot of time in these forums. I more than tripled my starting bankroll this year, but ran into some legal difficulties and other expenses which basically forced me to cut into my bankroll and move down a couple levels. Now it seems like I just can't focus in the smaller games- I just can't seem to get myself in the zone, and I'm playing like a donkey in games that I used to crush. If I'm reading a post on two plus two, or observing a game, I can think in a much more sophisticated, analytical manner than I can when I'm actually playing. I've tried hard to focus and clear my head before playing, but to my dismay I find myself continually making idiotic plays, being unable to think things through, and then repeatedly kicking myself in the ass afterward. It's particularly unnerving because despite making a conscious effort to play properly, I feel almost as though I'm not in control of what I'm doing. Really I'm just wondering if anyone has experienced anything like this, and if so how they dealt with it. Hell, if you haven't experienced it but still have a good idea of how to deal with it I'd be happy to hear it. Thanks in advance.