With regard to stimulants, if it does turn out to be Chronic Fatigue/ME, then these aren't advisable.
They don't actually "give" you energy, they just cause you to utilise your (limited) stored energy, faster. So you may get an immediate boost, but it will inevitably be followed by an energy crash of unpredictable severity/duration. This is not helpful in the working environment, as I found pre-diagnosis, when trying to kickstart my miserable system in the mornings with a triple espresso + four sugars.
I had a course of Occ Therapy from an NHS Chronic Fatigue Unit and they even advise against mild stimulants like caffinated drinks e.g. tea, instant coffee & cola.
If there are more tests outstanding, then I'd wait to see what they come up before making plans. Chronic Fatigue/ME is a diagnosis of elimination, given when all other avenues of investigation have come up blank.
Best of luck to you.