How Can ADHD Be Diagnosed?

Hi, I am concerned that I have ADHD, and i have tried making appointments with psychiatrists many times, but they are either not accepting new patients or are booked for months. I seem to have many symptoms of ADHD because I can t seem to focus in any of my classes, get distracted very easily, jump from topic to topic while talking, get tired easily, can t keep my attention on one thing for long periods of time, i am extremely unorganized as well. Even my professors have said my essays were very jumbled and unorganized and have questioned if I have ADHD or ADD. It is just extremely difficult for me to finish any tasks throughout my day, and I would really like some treatment.