The great news is that you're well-prepared for this appointment. You have a great sense of self-awareness and an understanding of your symptoms. It is likely that you may have ADHD based on what you've described.

I'm guessing, however, that your appointment is with a general practitioner and not a psychiatrist? I didn't read too carefully so correct me if I'm wrong. A GP can in fact prescribe ADHD medication, but they are not the most qualified doctor to give you an accurate diagnosis and treatment options. Your best bet is to briefly relay your struggles and symptoms to your GP and say that you'd like a referral to a psychiatrist to find out more.

A psychiatrist is better equipped to diagnose you because (assuming they are a GOOD doctor, which isn't true for all psychiatrists) they are familiar with the nuanced behaviors of someone with ADHD. A psychiatrist is the medical doctor who can test/evaluate you if they deem necessary, diagnose you, and prescribe medication.

However medication will not make your problems disappear completely and it is best to add therapy to your treatment to learn how to form new and healthy habits and routines. Find a therapist who specializes in ADHD, otherwise they won't really understand how to help you.