I could be wrong...but I feel there is some important info missing from your post. You state more than once that you feel guilty..and feel like you have failed him... and also believe that he feels the need to act like an adult and you feel nad about him not having much of a childhood...but then you say that you can not see any reason he would be depressed... so I'm a bit confused... children like Anna mentioned are highly impressionable. Especially a sensitive child who is in tuned to their surroundings. They tend to pay close attention to adults then other children. Overhear everything and pick up on and internalize adult cues more than age appropriate social peers. And generally as all children are looking towards close adult authority figures for reassurance. So home and parents/guardians/daily caretakers is the #1 source of info that your son is paying attention to. 2nd would be school/church, teachers, counselors, sunday school/ youth groyp leader, principal, and coaches. And #3 would be any other environment that the child is in care of on a regular basis...such as grandparents/close family who mind him at their homes..a few times a week..or spends wkend overnights with...and parents/adultsof close friends that he has playmates with regularly. So I guess when did the depression and physical symptoms begin? Who was he around the day or week leading up to 1st psychosomatic complaint?...or if this is a slower over time development...was there major life change like moving, death or other loss of close adult figure? And then what is your home life like? And have you suffered from depression or another MI previously or currently? Or anyone else that lives in house? Are there arguments or phone convoy that you talk about stuff that could upset him or worry him..even if you are in another room or after he is asleep? And what is sibling relations like both between them and you and other siblings? Could he be picking up on differential treatment of some sort? Idk I'm just sitting out ideas and thoughts...you may not have these answers but I think that they are important to explore and talk with his therapist about too.