Hi SFTYGAL,
I don't know what tests are being run, but a complete blood count is what is needed. If you can post the results or message me with them once you have them, it will be of some help.
I have a few questions.
How old is your daughter?
Is she now or has she taken iron supplements?
Does there seem to be any connection between eating and the stomach pain and nausea?
If the test I mentioned above has not been run, it should be, and you should also ask the doctor to check for both pernicious anemia, which is a vitamin B-12 deficiency and also for folic acid deficiency, because both can lead to nausea and might also explain some of her general symptoms. If these show normal, a hemoglobin electrophoresis test should also be done to check for evidence of any other hemoglobin variants.
You should be aware, if you are not already, that one of her parents is also thal minor. Also, she should know that when it is time in her life to consider children of her own, that her partner should also be tested for thal trait, as two minors can produce a major.