I was having similiar symptoms, the tiredness, no appetite and then big appetite, and feeling cold so I was checked for a thyroid problem. Sometimes when I'm very stressed out I lose my appetite and want to sleep all day. High school is such a terrible time for most young people especially girls. I would take her to the doctor and have them run tests and then get her to a psychologist as well for good measure.
I actually have days where I am not hungry, and I eat a balanced diet. I am underweight. I don't diet or purge. I have a hard time eating some days, but I just make myself.
YES! There is a high chance that this could be an Eating Disorder! Ednos stands for Eating Disorder Not Otherwise Specified and is basically the diagnosis for those with Eating Disordered Characteristics but not as extreme in nature as Anorexia Nervosa. The best news is that treatment IS available as long as you get your daughter help NOW! She seems aware that there may be a problem, so I'd suggest asking her whether she would like to come to the doctor with you to discuss the matter further.
I urge you, however to seek treatment ASAP. Ednos can easily transfer into full blown Anorexia or Bulimia Nervosa, it is also important from a physical health perspective as her bruising and tiredness are potentially the result of an electrolyte imbalance that can cause heart issues.
Good luck and Best Wishes.
u should get her checked for leukemia. if she is getting bruises for no reason. and for an eating disorder, just keep a very close eye on her maybe get her to see a therapist.