I have no experience with jumping, so keep that in mind while you read this. I do have experience with high-level games horses, though, and if they start getting sour, do something else. If you're getting her tuned up, try going down the road (if you have one that's safe to ride on) and work on things like leg yields or changing length of stride. I'm sure you'd know what exercises to do, just get her out of the arena for a couple days. Then take her back in, but for a day or two, don't even look at a jump. Let her relax and get her mind right.
The best reward for a horse is rest, so when you go back to the jumps, when she does one really well, show her by walking on a loose rein or just letting her chill out for a bit.
Learning never stops