I realize your comment is old but I just discovered this site. In general, regular physicians don't look at the "whole" person, so you definitely need to find someone who will. This can be a naturopath, or even a chiropractor with a sub-specialty in nutrition. They can do blood work and saliva tests to determine the possible sources of your daughter's obvious imbalances. After all her time on antibiotics, she should definitely be checked for yeast overgrowth, which is a fungus that can spread throughout the body and cause many different symptoms. I hope she's on a good probiotic. There are a couple of independent labs which test for yeast via a urine or poop or blood test (my son had it done but I can't remember which one was for the yeast). A food elimination test might be useful to determine if she's eating something that she's sensitive to, and can help to rebalance her body and get her back on track. But clearly things are not working in synchronicity and most regular MDs are just not equipped to deal with that. There are some MD and naturopath combination doctors, as well.
I cant find where the comment said anything about yeast, however harboring of yeast especially in an adolescent can be a sign of Diabetes. Take notice if the child urinates frequently, complaints of burning urinary tract, and excessive thirst. A good common test to request would be a Hemoglobin A1C. Therefore, the Diabetes could be a primary source of the yeast, then its spreading would be common. As for the Strep, As a teenager I constantly battled strep. I do recommend tonsillectomies, especially while they are still young because the older they get the more uncomfortable the procedure is. Make sure the throat cultures are coming back positive and not just the blood work, because contrary to common belief strep can infect almost any part of the body. That said a tonsillectomy doesn't insure a strep free body. Another recommendation is consult a infection control doctor in your area.