Catastrophic Reaction to pain

My mother, 83 , Mixed Dementia (Vascular & Alzheimers) mid to late stage, lives with me and has been Physically able to transfer and walk with a walker us to this point. However, she had a fall last week, and even though she didn't fracture her hip or pelvic area, she is reacting to the pain in such a severe and dramatic fashion, i thought i was making it worse by helping her up and down. I was sure they missed a fracture in there at the ER, but even second opinion Urgent care said no fracture and she is reacting this way out of fear. The last two days have consisted of me not being able to get her to go to the toilet without very loud child like cries and moaning, even though she can be distracted very easily to stop that and look at a squirrel or something out the window. It is very strange. She reacting like she is being cut in half with a saw, if i just get her to shift a tiny bit. Yet once she is up and using the walker she is strong and has a good gait, but just freaking out. I don't know what to make of this new behavior. It has gotten slightly better every day since, and they gave us muscle relaxers to un-tension her back muscles. But she has definitely declined in her speech abilities and been more anxious than ever before. I wonder if anyone else has experienced this kind of over the top reaction to pain or anticipation of pain.