I think you should take him to a doc too
I don't think its really normal for a child to be unhappy most of the time. Teenagers/ pre-teens can be "irritable" or "angry" but mostly at their parents:) Not with friends, and not all the time.
You should see his dr, and probably ask for a referral to a child psychiatrist. Depression/ anxiety is treatable, but as you know, rather dangerous if untreated. Better safe than sorry, I always think.