I think meeting with a mental health professional at the school counseling center was a very wise decision. They can assist you in multiple ways including: assessing your symptoms to determine if a mental health disorder is present or referring you for a more thorough evaluation, if necessary. They can also treat your symptoms in the short term, which may both decrease your anxiety and improve your overall quality of life.
One of the main symptoms of DID is memory loss. You experienced some memory loss but it’s fairly minor. There may be other, more severe instances of memory loss that were not included in your letter. An in-depth evaluation could determine if your memory loss falls into the range of “normal.”
You may also want to consider having a neurological evaluation to rule out any medical problems. It is important to rule out all medical explanations.
I would also recommend keeping a daily log of your symptoms and memory loss. Documenting your symptoms may uncover unique patterns. That information would also be helpful to your treating physician and your therapist.
Finally, it would be advantageous to continue educating yourself about DID and other mental health disorders. Many people experience a variety of symptoms but don’t meet the criteria for any one disorder. Your personal history is characterized by trauma which may be contributing to your difficulties as an adult. Psychotherapy may greatly assist you with this.
Please take care. Best of luck to you.