exhausted

I think you have come down quickly to 6 mg. You could try to take 6.5 or 7 mg. 4 - 5 days and see if that helps. If not then you can go back to where you are. But you are probably right your adrenals are struggling to get to work at the moment.

At 7 months you are likely still quite ill - this is not a short illness - and just because you are only taking 6mg, it doesn't mean that's actually what you need to make you feel a bit better. 

What you have to realise that it's not about getting off pred, it's about getting to the lowest possible dose where you feel as well as you can, bearing in mind you are still very ill. I would think that 6mg is probably not enough at this early stage - only 7 months in - most people would be happy to be down to 6mg after a couple of years. I'm entering my 3rd year and have managed to get down to 7mg with the help of Methotrexate, and tbh I'm pretty happy with that!

I would suggest you might want to try increasing the pred a little and see if you have any improvement.

I agree with FlipDover that, assuming you are referring to PMR, your dosage seems very low after only 6 months.  Usually PMR dosage starts at at least 20mg and could take a couple of years or more to work down to zero.  As for the fatigue, don't know what dosage you started on but if it was under 10, your adrenals are probably fine.  I found that fatigue settled in for awhile each time the dosage was reduced.  I was told to expect this for several days but for me it lasted almost til the time of the next reduction.  As was also previously mentioned by others, if you felt good on your last dosage, you should probably go back to that...or talk to your doctor about an even higher increase.

In retrospect I think I took about eight or nine months to get from 15 to 6 mg.  I started dead slow reduction taper at 10 mg.  But I began to feel tired at 7 mg.  It just means your adrenal glands are not waking up instantly after going on holiday while you were on a slightly higher dose.  I think it is probably more uncommon not to feel fatigue.  How do you deal with it?  Personally I think if you have no or insignificant PMR symptoms you should ride it out.  Prednisone is not good for us and the lower we can get our dose the better.  But if you have PMR symptoms, go back to where you were comfortable for a while and when you are stable again, reduce verrryyyy slowly  Fatigue will likely return as you reduce again.  I found there were a couple of places where I was particularly fatigued and 7 was one, 5 another.  Now I figure I'm going to behave as lazy as I feel and if husband doesn't like a dusty house he can d*** well do the vacuuming.  Etc.  Eventually things should get back to normal, whatever that is.  I'm told it can take up to a year after last dose of pred for all the adrenal-related hormones to be back in balance.  Sigh.

The other thing to remember is that it's not just the pred, or lack thereof, which can cause the fatigue. The disease itself causes fatigue. It could be that the pred just isn't masking it at this level/