Cbifoja, I arm going through something very, very similar with my 10 year old dd! My DD's fear didn't come from a fall, etc, but from bad coaching. But she still has problems connecting her layout flyaway to the giant-giant. I too, felt sick when she was crying in bed at night. This is what I did:
1) explained to her gymnastics is not her whole identity. My dd was known as the best bar worker in optionals. She took huge pride in this. When she had a set back on bars, it really shook up how she felt about herself. I showed her a piece of polka dotted fabric. I told her that she is the piece of fabric, and just one of those dots is gymnastics. That she is great at a lot of things, and that gym only makes up 1/100 of what is special about her.
2) I told her that everyone in gym has setbacks. Every single person. And that there is no rush at all to get the skill. It will come when it's the right time.
3)our family could care less how long it takes her to get to level 10 or even if she chooses to keep doing gym. Completing level 7 is an accomplishment at any age, and we are super proud of her!
4) if she got a new skill on any other event, I made a big deal of it- "yay, a BHS-BT on beam, that's awesome!" Etc. I never bring up bars ever. If she does, I say " wow, great progress!"
I doubt it's hormones. It's the combination of practically living at gym and being a very young level 8. I hope she feels better. Mine is training with a new coach. He is very supportive and kind. My DD is progressing slowly, but she is back being happy! I hope your dd will be happy soon too