Since you just planted them, it would be alright to dig up your crape myrtles and loosen the roots. You can also get a better sense for how you are watering and make sure that you are getting it wet throughout the root area when you water. 
But also, new plants do experience a little shock when they go in the ground. Especially with the wind and heat we have been experiencing. If the plants are wilting during the day but not looking wilted in the evening or morning, that's normal. Plants will wilt during the heat of the day to conserve moisture. 
Another thing to do for your new plants is to mulch around them which helps hold in the moisture. 
Let me know if I can help you further.