From what I understand of ring play. Your sample size *is* too small to draw definite conclusions. However, that *does not* mean it is meaningless.
Also, no one has really addressed what can be expected as a win rate at 10/20. I don't really know but it seems 3BB/100 is most likely overly optimistic. At the same time I've seen some of your play and it's very solid. I doubt the bad run is due totally to tilt and I doubt the good run is due totally to skill.
All that being said. The ~+1BB/100 combined is nothign to sneeze at especially considering you sort of came straight from 3/6 (where your sample size is also too small for definite conclusions).
As for reasons for your stats. Variance is 99% of the explanation for them. If this is what you're calling 'bad luck' then so be it (although there really isn't anything such as bad or good luck).
My advice is that as long as you're not tilting or feeling that you're playing sub-optimally and can stomach swings in the 10/20 then continue to play them. If you don't think you can handle another 8,600 hands at -2BB/100 right now, then drop back down to the 3/6.
As far as plugging possible leaks -- go ahead and post hands that you felt were tricky. Also feel free to identify the most common situations where you *might* be making mistakes. Obviously those specific situations would be the 'leak' if you're not playing them very well.
If you need a support group then visit the following forum and post on it at least every day:
QLC
Yugoslav