Mark has a good point that you certainly are taking the correct steps for getting your son help. But there are other really important things that you can do do help him and you.
The first is to learn all you can about ADHD so you do know what is going on with your son.
This link give good overall information about ADHD with lots of other information. The link is - http://www.help4adhd.org/en/about/what/WWK1
This link gives you some very good ideas of things to do to help your son and you deal with his ADHD. http://www.onhealth.com/tips_for_parenting_a_child_with_adhd/article.htm
Also, besides the last link, if there are some specific things he does that are just driving you crazy - I can probably find something to help with that.
Best wishes.
It really sounds like you are doing everything right. It also sounds like you are taking your son to a doctor that is thoroughly testing him for ADHD. I would just follow through with the testing and with whatever the doctor recommends.
No one can actually tell you or give you an intelligent opinion as to what is going on with your child unless you son receives a thorough evaluation. It sounds like you are midway through that process.