Shade. Put it in shade. Be prepared to put it into a humidity tent if it doesn't pick up markedly in the next few days.
This is exactly what happens with too much root removal in repotting!
Leaves can emerge utilizing only the water stored in the stem xylem. After this, a tension is created (by transpiration) that would draw water from the roots. But, missing the capacity to take on enough water, one gets droopy foliage and buds failing to extend.
Your mission is to buy time - keep it from desiccating while new roots develop that can support the load. Those buds and leaves are the auxin sources that stimulate the needed root growth. In other words, reduce the water loss to transpiration --> elevate the relative humidity around the leaves.
Full recovery could take quite a while (like 4-plus weeks). Inaction/impatience will be rewarded with a dead tree.
Once it perks up again, introduce it to the normal conditions of your garden.
Or maybe it is something else - careful observation of it in shade will tell.
btw, things don't look all that alarming in your pix.
