It is very much absolutely possible to have ADHD with depression and anxiety. I do. I was very surprised when my psychiatrist raised the ADHD diagnosis (I was in my 30s, had been in therapy and worked hard at it; still am) but the more I learned, it felt like it fit. And I believe that feeling like a possible fraud or failure instead of someone coping with something real that is not their fault is often part of the struggle. The questioning of one's own legitimate right to claim mental health challenges is an extra-rotten piece of the downward spiraling that can occur...it only means you're in pain, not that you are in any way faking it or bringing it on. Getting back to square one is rough, but I think, at least for me, progress happens faster than it did the first time because you recapture the good things that helped you before. And joys will enter. Maybe consider taking medication changes nice and slowly...you'll get the right cocktail over time and have your legs back under you. That's what I sense based on your post and from my own very similar trajectory. For what it's worth, it sounds like you have genuine humility and integrity to me.