Since her Thyroid is low, look to her diet. Does your child consume foods with iodine? Normally it would be in iodized table salt (not packaged foods like chips, etc), cold water fish (not fish sticks or canned tuna), or in kelp supplements. If none of these foods are in her diet, you can ask your doctor about supplementing her with kelp. Iodine "feeds" the Thyroid and can cause the symptoms of low Thyroid while the tests are within normal range, but on the low end.
i would have her checked for diabetes....146 is high! the wetting is also a sign...does she get thirsty alot?? let the pediatrician know of the sugar test you got.
good luck
It does sound like possible juvenile diabetes. You can also look up Sub-Clinical Hypothyroidism. A good Endocrinologist may be willing to treat the Thyroid problem even though it is not as low as is typical for Hypothroidism. The lab may be basing their figures on her weight, and because she is already underweight, she falls in the low normal range. Also different labs use different standards sometimes. A Dr. may only go by what their lab sheet says, and not look up what it really should be for a specific person. If you can't get an Endocrinologist, try to get a Pediatric Gastrointerologist. How tall is she? Low thyroid can stunt growth, and cause a long list of symptoms.
recently my daughter was doing the exact same thing. She had a fever for a night i medicated it and the next day it was gone for the the next week she was not herself and had 2 accidents. She is 3. She wasnt eating and kept on saying that her stomach hurts. I finally took her to the doctors and she has tonsilitis and an ear infection. The thing is she still wont eat she says that her stomach hurts and all she wants to do is drink and alot too.