Lisa, You absolutely have to have the blood test. It is called TPMT. Your doctor should be aware of this already.
I'm sorry you're doing so badly. Imuran/Azathioprine can take some time to kick in, so you might still need other treatments if you get worse.
Sometimes Imuran works and sometimes not. Some people do better with Cellcept. It all depends. Imuran has been around much longer and is the more "tried and true" immunosuppressant.
I hope it works for you! Take it easy. You don't need to get worse.

Annie