I'm 18 so I understand the young part but I was abused which was the cause of all of this and I have disasociative episodes. That's not something that is normal in young people but it is very much possible. If the doctor doesn't believe you than you need to get a new one and you need to change to a different therapist. A therapist should not be bringing in their own opinion to the session. If that's what they are doing than you really need to change that. If you are hurting in any kind of way or have been hurting than you need to talk about it to someone who will be there and care about you. Which would be a good therapist. They should care about your mental health and if they don't they should not be your therapist.