It may not do any good to report her. Stand your ground on what you don’t feel you can do. She cannot force you to do a sit to stand.
If she verbally abuses you again, or in any other way, like force bending your knee to show she’s in charge, tell her you will not tolerate that kind of treatment and that you are going to go somewhere else and walk out. Taking your business elsewhere will be the best way to go. Unfortunately, if they are that busy they won’t miss your income much, but you’ll do better somewhere else, even at home on your own.
PT is truly not essential and especially the “therapy” she is offering you is doing more harm than good, both physically and emotionally.