Thank you all for your responses. My husband remembers Sammy running to greet him a couple days ago and doing a back flip when her body caught up with her.

She is always too excited to see people and she does not think about slamming into things or belly flopping on the floor when her feet fall out from under her... I don't know how to keep her from doing those things once she feels better and I worry it could happen again
She is pretty zonked out from the meds so that is good. I had thought she was just tired from having a rough night and going to the vet but she is still very sleepy so I hope she just sleeps it off.
Does anyone know if it's possible that she hurt herself on Monday but didn't show pain until Tuesday night? We think it took that long to swell up. I just touched the spot again and she did not seem to tense up so I think the swelling has gone back down. My poor little monkey. She has been through so much. All we can do is love her.