Hi, thank you for contacting Just Answer. My name is XXXXX XXX I am a mental health counselor. It sounds as though he could have developed some separation anxiety and adjustment disorder that he does not understand causing him to be anxious because he can't explain what is going on for him. I would also ask him if he is having any kind of dreams and if so what are they about. It is not uncommon for someone who is sensitive to react negatively to a change if even they first perceive it as a good change. However, since his reaction is more dramatic than normal I would probably take him to see a counselor if these behaviors continue for more than a month. It is also possible the reaction is stronger because he is going into puberty and his hormonal changes may already be acting up causing more feelings he is not use to. I hope this answer helps you.
Please let me know if I can assist you further in this. If this answer has helped you then please press the Accept button at the bottom of the page so that I can be paid by Just Answer. Also, please fill out the feedback form so that I can know how to better serve our customers. Again, thank you for contacting Just Answer.