Diagnosed with ADHD last week

Hello,

So, I have been diagnosed with (severe) ADHD last week. This was a long time coming, as I was more certain I had ADHD than I had ASD. I have been placed on a brief waitlist to start medication (lisdexamfetamine) and psychotherapy. 

Unlike ASD, I feel like ADHD has completely ruined my life. It ruins everything, on a daily basis, for me. The rejection sensitivity is by far the worst thing for me, although the hyperactivity and inattention are also extremely, incredibly infuriating. 

I recently got into an argument with my university because I felt I was being unfairly excluded from an Open Day event. The university wanted more gender representation but knew I had a registered disability and had been warned about the recent ADHD diagnosis, too. 

I sent this email when I refused to meet and discuss it, offering an idea I had: "

Hello,
I’m sorry, but I am deeply uncomfortable with discussing such matters in person.
What I could do for the 25th is have a separate stall advertising undergraduate projects? I have also participated in all 3 of Posters in Parliament, BCUR and ICUR. As this was the highlight of my time here, I think many will be interested to hear about this opportunity.

"

This was the response I received: "

I understand it can be hard to talk about these things in person. It is also difficult to read tone in email and often means people can appear more forceful than intended. Part of what I'd like to support you with is how you might approach this sort of thing in a different manner to that which you are right now; this is the sort of thing which you are likely to need to navigate going forwards.  In part, this is to help you with your communication and social interaction in the way you are dealing with members of staff in the department, which will also be useful with future employers. 
I understand you feel working as an Ambassador is beneficial to you and we value your contribution, but it is not appropriate to dictate that you will work. You have had equal access to the job and shifts and we will not discriminate against you or others on any basis - this would not be a reasonable adjustment. I have checked with Disability Services and we are under no obligation to roster you on for more sessions than others.   In addition, the work is not a requirement of your degree. 
As I advised you on Monday, we do not need you to work on 25 October.  I know this is not the outcome you wanted, but you do need to respect the department's decision on this.

"

When I saw that, I almost had a panic attack and spent the whole evening yesterday trying to calm down instead of studying. I simply do not understand what I did wrong, what I said, to deserve that sort of response. The person who wrote it not only knows me personally, but also knows I have ASD, ADHD and have been through terrifying events this year.