My doctor seen a 2mm kidney stone in a xray on 3/7/12 and I still haven't passed it. Is this normal?

Yes. Stones can take a variable amount of time to pass. This is a rather small stone and hopefully will readily pass in the near future.
It may never pass. Stones in the renal pelvis (kidney) seen on xray may or may not pass. Some stuck to the wall of the renal pelvis and never move or cause problems. So, u have been lucky so far. 2mm is small and will likely pass, but will cause some pain.. You will know when it is passing down. Keep up your fluid intake, for life! good luck.