Personally I'd go play cash games, possibly at a slighly lower limit than normal. I hit a bad patch this week attempting single table sng's myself so stuck myself right back on a cash table & told myself to take my time. Getting my confidence back was my first priority and a few wins did that.
Once you've done that, go back and have a look to see if you really have identified a weakness. Were you putting money in while behind, or were you just getting unlucky? If you spot any problems then that's a great sign so don't worry about it too much. By identifying things like this you're giving yourself the chance to become an even better player. Don't ever worry about finding a problem, instead congratulate yourself on spotting it!
My lesson this week was that I realised that I was trying too hard in the sng's, I was aware of the blinds increasing so was too impatient in trying to build my stack and ended up busting out far too soon. To correct it I've started multi tabling, on one table I'm playing a bit tighter than normal in my regular cash game, on the other I'm playing a single table sng. It's slowed me right down in the sng, any time I worry I'm playing badly because my stack is a bit low I can look right back at the cash game. It gives me an independent measure of how well I'm playing, keeps my confidence up and lets me make more objective decisions about when to push.
I'm still not great at sng's but I'm definately improving just by taking my time. My biggest weakness now is deciding I like a hand early on and not laying it down when I'm beat, or spotting an opponent who'll call with any two cards and figuring any hand can beat him. I don't do it in a cash game, but my aggression and impatience is taking over in a tournament.