if this was me I would be checking with my doctors. some medical conditions do mimic mental disorders like lack of affect (not having and emotions connected to things you have or are experiencing), depersonalization, derealization, numbness. many medications can also produce this feelings such as antihistamines, antidepressants, cold remedies, analgesics.. some foods, chemicals, food processing chemicals and food allergies can also produce some pretty strange symptoms if you have a sensitivity to them.

I would also be talking to my mental health people because many mental disorders not just dissociative disorders and reactions can also mimic and produce these symptoms.

other things can make a person feel like this too like fear of getting better, fear of not getting better, fear and anxiety over beginning or ending treatment programs.

Some treatment / therapy programs and techniques do have elements of detaching the emotional aspects so that you learn to automatically remain stable, non emotional when dealing with your problems and everyday life. most intensive treatment programs that I have attended and know about through work and classes, do require the clients to learn how to look at their life and problems from a logical non emotional stand point and learn tools that will quickly bring them out of emotions such as anxiety, stress, panic attacks.. and do what they need to do to remain stable. if your intensive treatment program had this standard component of learning grounding, self nurturing and emotional distancing and addressing your problems in a logical manner its no surprise to me that you are carrying over this feeling of remaining emotionally detached as you terminate this treatment program. your body is doing what you need to do to remain calm and deal with the fact that you are ending a part of your life and moving on to the next step.