Violation of privacy

I sent a letter to the dean of a program at my college(dropped of to front desk). They assured me they wouldn't talk to my teacher since I wanted to talk to them first. This was about me having ADHD and this impacting one of my classes for the spring. I went to the dean since I knew my teacher would say she couldn't help me. The last sentence was please keep this confidential since I would like to tell my teacher. My teacher knew I had a concern but I didn't tell her my diagnosis yet. It's not that Im embarrassed but feel the dean gave the letter to the teacher and never contacted me. I understand the dean didn't feel they could help me but I would have rather told my teach in person. I am in college and a health major but isn't that wrong to divulge my medical info without consent?