Have you tired different depths? Maybe really really shallow, then try really really deep?
It could be related to something developmental, where she is more aware of dangers.
TBH I would just wash her down with top and tail solution and a cloth until she gets over the fear. My DS hated baths from birth (believe it or not!) and I only put him in about once per week or less, just dip him in and see his reaction. Different depths eventually helped, he liked really deep a couple of times and after that really shallow so it was a bit of trial and error. It wasn't until about 5.5 months he enjoyed a bath so it was a long time of washing with a cloth but he was still clean.