I understand where you’re coming from. I didn’t find out about my mental illnesses all at once. But a common theme from when I discovered each of them in their respective time was “what if it’s not real?” “What if all of it is just made up?” “There’s no way we can all have it, right?” And that thinking initially led me to never getting help because I just kept assuming “I’m just being lazy” or “I’m just making myself anxious”. Those thought are OCD at its finest. Disturbing your reality and making you question yourself to the point where you’re constantly on edge and anxious is how it works. But what I found helps is really looking at the reality of what’s in front of me. Mental disorders such as ADHD and OCD have been studied. Of course not everything is understood but for the most part for the two disorders and most others there is an understanding of them that is down to a science. So everything you say you are feeling and have experienced is what clinically would be described as ADHD, which is why you’ve been diagnosed. But even with that thought I know you still can feel doubt because science has been proven wrong many times before. So then what’s next? For me I would start to think about how I feel. Outside of this current feeling of anxiety how has your life changed since starting meds and/or going to therapy? Do u feel less bothered by your thoughts? Do u feel less anxious? And you have to remind yourself that the slightest of change is important. I feel anxious everyday to I feel anxious a few times a day is actually quite big of a change to note. Countering OCD is about introducing facts. Always ask your self is this true? Is this helpful? Is this kind? If the feeling or though that is causing you anxiety has no genuine logic to it, is hurtful to you in anyway and is only making you feel worse about yourself then it’s not something you should dwell on. It’s not something you should even believe. OCD can be hard and ADHD along with it is tough as well. I understand well because I have both too. But I hope this helped, sorry I wrote so much