Double by the GP - which bit of little steps don't they get
Why would a GP think that an increase would help fatigue?
Was that double all at once? Which may be far too much far too soon - no wonder the body reacts. As oestrogen levels drop muscles may become lax = aches and pains.
Have U had recent blood tests done, particularly for thyroid function and VitD levels? Both can cause fatigue.
Let us know how you get on. Personally - although I don't use HRT other than for vaginal atrophy - I would drop down to the initial dose and increase gradually, giving my body time to react to the uptake. R U getting periods at all?