Can anyone help?

My 5-year cat took a flying leap off the deck 2 1/2 weeks ago, after being startled by an unexpected visitor. She fell about 15 feet to the ground, and tore ligaments in her back right leg. I took her to the vet, who sedated her and applied a splint which was removed on the 5th day. She was on pain meds for a week following, and it seemed she was starting to gain some mobility. Although eating and drinking little, she has been content and sociable whenever we come to check on her, but limits her activity and keeps to herself. The last two days she has greatly reduced the amount of moving around, and is clearly experiencing pain again. She doesn't use the injured leg hardly at all. Has anyone had a similar experience?