I’m sorry you are experiencing this. No one deserves to be treated this way. If the person you went to with your problem did nothing then go to a person who holds a higher position. Document everything, date, time and experience. A good website for job accommodations and suggestions is “https://askjan.org”. Know your rights and try to find an ally you can trust. Remember HR works for the company, not the employees, but if HR believes the company will be hurt by the behaviour of the employees they will sit up and take notice. Remember all that you have accomplished in spite of your ADHD, if the people making your life miserable had to have our ADHD brain I wonder how well they would do.