To help you figure out how your rabbit is feeling, some people choose to offer their buns a very special treat once in the morning, and once at night (12 hours).
For my guys, it is a single Craisin. They only get 1 in the AM, and 1 before bed.
If they don't go completely nuts over that Craisin, then something is wrong, and I treat it as an emergency.
This system might help give you a safety net for judging your bun's health status.
Agreed, cut back the treats significantly. Otherwise, you will never be able to tell whether she just isn't interested in the treat, or she is actually sick. Rabbits shouldn't have more than a tablespoon or two of fruit in a day, due to the high sugar content (causing obesity in the long run). Too much sugar can also throw off their stomachs. Keep a close eye for belly bloating, or if she is pressing her stomach to the ground in pain.
Keep rabbits sugar-deprived, and they will always be responsive to treats (unless something is very wrong)