Yep, they said it. First get you blood tested for thyroid problems. That should be part of the dx procedure for ADHD anyway.
Once you get that excluded you can continue the diagnostic procedure to determine if there is more going on.
On the add forum I visit and help mod I often find that many people have a difficult time getting diagnosed. And sometimes the docs will experiment for a long time with various med setups until they find the right combo. Its happened that someone has been prescribed anti depressant meds without result until they tried an ADHD specific med which turned their life around.