There have been rumors abounding as to why this is happening.
One that makes sense, is a bad batch was made for some of the biggest pharmacies in the US and it will take some time for a replacement batch.
There is a great compounding pharmacy in Oregon that makes it for a great price. You do need a doctor to send the prescription in though, before you can order. Stroheckers is their name, I believe. My doc gets his stuff from them, and wrote me a script when I moved.