Firstly as someone in the Uk who has been waiting 2 years to get tested contact your GP as soon as possible. If they hadn’t wanted to test me for ASD first the waitlist can be up to 6 years for an adult.
I have not spoken about my ADHD suspicions with parents but I have with my cousin who is older and her brother was diagnosed ADHD as a child.
I asked her to go through the checklist with me because I identified with the symptoms and asked her to tell me if there was anything she could think of about me when I was younger that hits the criteria.
In your case you could tell them your roommate brought it up and ask them to go through the checklist with you because your concerned and you have been having issues at uni.
On the uni point, have you thought about contacting your disabled students service? They might be able to give you advice / support and potentiality might get the diagnosis boat going faster.