Separation Anxiety Support Group
Separation anxiety disorder (or simply separation anxiety) is a psychological condition in which an individual has excessive anxiety regarding separation from home or from people to whom the individual has a strong emotional attachment, which can occur at all ages and in many situations.
It does sound like you have a debilitating case of separation anxiety. Not being able to eat, concentrate, sleep, or have an upbeat mood is definitely is a flag regarding your emotional/physical (presence) needs.