Probably you touched the roots, so the plant need some time to restore.
Additionally, "Supermarket" usually have plant in shadow (most of the time). It is possible that now it is receiving too much sun (and suddenly). Ideally you should let the plant to adapt slowly (e.g. to put them in half shadow for a week or so (especially in mid summer).
I think you should just wait, and the plant should return to original form.
A small trick: you can spray some water to the leaves: this will get some water direct to leaves, so it will not dry out, it will not damage roots with over-watering. Just few times, before the plant restore. It should really use roots, but on short term, until it regenerate the tips of roots (and with hot weather) this could speed up the process.