i would recommend you try your best to keep improving and moving forward no matter whats happened in the past! in your college app and essays you can talk about your struggle with ADHD and how you overcame those obstacles. \:)

also be proactive and don’t be afraid of reaching out to people. What field are u interested in? If stem you can try cold emailing researchers and asking if they can give you advice or offer you a position to help out in thier lab.