Sleeping on wet hair is asking for frizz. I sleep on wet hair only if it is braided or in twists. I take them out in the morning and wear it as a style. It adds length too. I have major shrinkage, which is not the style I am going for all the time.
Try using a curl definer (esp one you can rewet) when you comb your hair wet, let it air dry, and pineapple your hair at night (this also stretches). You can mist with h20 and go in the morning.
IDK if this helps.