Go in the pool when she is hungry and give her the best treats possible when she is standing on the deck. Then gradually let her put one foot in the water to get a treat and build it up slowly. It has to be her idea to do this.Take your time. You need extra time to get her confidence in you back. A child might feel supported by holding them in deep water but most dogs freak out as you know. Unlike for children, "coaxing" is too close to "forcing", according to dogs.
Deja, GSD, sable WL, female, born 11 / 2013
Cam, Rough Collie, sable, male, born 8/2015