Hi. I was a child that suffered from anxiety... whether it was seperation or something all together different, it was still the most awful part of my childhood. I did NOT want to go to school. I threw up every morning. I cried. I went through the school day completely numb to all that was going on around me. Looking back, I don't even remember much of my childhood because I COMPLETELY blocked it out. It's a miracle I passed, but I was certified as gifted so I didn't need to study to float by - lucky me. Please, please, listen to your child. My parents did and new that I was in some trouble, so they pulled me out and put me in a private school with smaller classes and more personal attention. I made it, and graduated (but not after trying to quit school my Junior year. I then went on to college with no fears or anxiety, but I have to say that growing up, becoming an adult, and having to deal with the "real world" has once again put me into a high anxiety state. It comes and goes, and I'm on medication. But when it's here, I just feel like it will never get better. So, to sum it up, give him all your loving support and all the help you can, but know that most young suffers never fully recover.
Sounds like anxiety to me but I would not be so quick to label it "separation". There are several disorders that fall under the anxiety category. I might suggest you do a search of the internet using terms such as "childhood anxiety" to see if any of the behaviours described are similar to those of your son. Since your son in incapable of doing his school work at school (a common behaviour for children suffering from anxiety - actually the anxiety can block a child from learning at school), I would suggest you contact your family doctor. If he/she thinks your son would benefit from treatment, then ask for a referral for a specialist with experience in anxiety disorders as a child psychiatrist, child psychologist, child neurologist, pediatrician, etc. It has been estimated at between 6 and 7 percent of children suffer from anxiety so you are not alone in this fight. Anxiety disorders are highly treatable. I wish you the best ...