DS calibration problems

I think this is quite a common problem for the original DSs like mine: My DS calibration has gone really weird. When i touch on the screen, it registers it about 1cm to the left of where i actually touched. This is really frustrating because it makes it very hard to play many games, as lots of them require the touch screen. The annoying thing is though, when I try to recalibrate it, after I have touched all 3 squares, it just restarts again, going in a contiuous loop. No matter how long I sit there touching the squares it never finishes. But, I recently found out that if I touch even farther to the right of the square than how it was calibrated before, it finishes. Of course, the problem then being that it's even worse. So, I tried again with the calibrating, and found out that the closest I can get to the square - with it finishing - is as close as it was before I starting trying to recalibrate. I have tried lots of things like cleaning underneath the screen with a toothbrush, but nothing ever works. Any help will be MUCH appreciated.Thanks

do you use a screen protecter of any type? the ds touch screen is pressure sensetive instead of heat sensetive if that helps