Process of getting diagnosed with ADD?

I'm 21 and I'm almost certain that I have ADD (since childhood)...I've read about it and I have the symptoms. When I was 15, I went to the doctor and asked about what we could do to get me tested for it. He talked about giving all of my teachers an evaluation form to fill out about me and have them watch me in class or something? I was embarassed and decided that I'd just cope with it on my own. I'm in college now and it's really taking over me. My grades are suffering because I get so damn distracted and I'm disorganized. I HAVE to do something about this. So I'm going to make an appointment with my doctor to see what we can do. But I've read some places that it's a complicated process. What will happen? I start school again in August, could I possibly be prescribed something by then?