You actually do not want anything that should be prescribed by a psychiatrist to come from a GP. ADHD is real and part of psychiatrist’s bread and butter so to speak. You wouldn’t go to your GP about a tooth, you go to the dentist who would then listen more specifically to your symptoms and experiences. There is nothing too small to mention at the initial appointment. Well it is true that looking things up online or in books one can diagnose oneself with just about anything, just leave it to the professionals. You will be heard. I’m sorry you experienced that.