Man... i may be wrong, but i think any learned skill is improved by exercising, and decreases with lack of it. So the way to get back your old proficiency in it is practicing it again.
The same happens with me with, for example, playing guitar. After one or two weeks of daily practice i can play really well. But if i stop, even if only for a couple of days, i lose a noticeable amount of the ability, and must exercise again to get the old level of skill. Of course the amount of work needed is not the same as it was the first time i played, cause some amount of skill remains longer with us, and thus is easier to get back the levels you already got once than reach them for the first time.
So i think the only thing that can help you is to sit and practice it again. It will take some time and effort until you reach your old levels, but surely the time and effort will be smaller than the effort you had to spend the first time you practiced it.

PS. Or something that occurred me right now... for me, weed helps a LOT to sense and control energy. So maybe if you do your exercises while high you may feel some difference. :jointsmile: