I can’t make a diagnosis on the basis of a letter, of course. What I can tell you is that you have cause for concern. You need to see a doctor and a mental health professional to get a proper evaluation. Please see your physician first. There are many medical conditions that can cause a person to feel depressed and irritable. You want to be sure that you are medically healthy, in spite of the anorexia.
It could also be that what you describe as “mild” anorexia is more serious than you are admitting, in which case you may be suffering from the effects of malnutrition. Your doctor might also refer you to an endocrinologist to make sure your hormones are in balance. The teen years are often a time when there are hormonal difficulties. It’s worth checking out.
If you check out as medically healthy, then see a mental health professional for an evaluation. It’s important for someone to meet you and to get your whole story, not just what you can put in a short letter to me. Once you’ve had a session or two to explain what is going on – both inside and in your world – a counselor will be able to advise you about what may be wrong and what to do about it.
I wish you well.