Have you had adrenal testing? Did you do a saliva test?
These are important things to discuss first before getting into this.
What is your thyroid histroy and how did you discover adrenal fatigue? Do you have current tests to share on this board?
The saliva test can be purchased by you if you choose IF your doctor does not use it. It's a good tool if you have the money to do it on your own to use with you other labs as comparrison.
It sounds like you have quite a history in thyroid problems - can you share?
P.S. - If your doctor put you on a T4 medication, it's almost always OK to just go off it cold because of the long half-life of T4 (~7.5 days). I.e. you depend on the long half-life to provide a slow wean. But depending on how long you were on the T4, it may take quite a while for your system to recover from the shock.
I would find another doctor before I started self-medicating with cortisone.
The adrenals need to be treated first, or in conjunction with the thyroid.
Find another doctor.
Your doctor is an IDIOT.
He should have offered you a 4-sample saliva test to verify what's happening. But most MDs are too pig-headed to do this.
Check out William Jeffries book on the safe uses of cortisone. you can supplement up to 20mg of hydrocortisone per day safely. The dosage just has to fall over the course of the day, e.g.. 7.5mg am, 5mg noon, 2.5mg evening. You can also take a low dose of DHEA, e.g. 10mg, in the morning.
I was on this program for months. It helped. It doesn't sound, though, as though my problem was nearly as dramatic as yours.
If your doctor won't cooperate, find a good naturopath.