I had no idea either what "monophobia" was until I googled it just now. It says
"It can be seen from this that agoraphobia tends to reduce self-confidence and the belief that activities can be carried out alone. It can be a short step from here to a belief that being alone at all is not safe. ... also believe that he or she will die or collapse or do something terrible when panic strikes and this too might make having a trustworthy person present seem as if it is essential ... A parent might be more available and might more easily fall back into the mode of looking after this adult as a needy child again. ... As with any anxiety disorder, monophobics cannot be talked or bullied out of their problem. ... /the anxiety/ is operating on the intellectual level of a young child ... a structured recovery programme where this person is alone for gradually increasing periods. ..." (Source:
www.anxietycare.org.uk)
I would theorize that your anxiety, which forms a part of you now, is operating on very much the same intellectual level as this little cute puppy in this film on dog separation anxiety. Look how many times the dog trainer trains the same little sequence; puppy at home alone him leaving house. He says one important thing in the film: "follow-through is the most important step ... it must be completed, if you don't complete it the dog wins."
https://www.youtube.com/watch?v=6Lbjxq0p_x8
Remember too they never treat these little puppies with medication, they always treat with repeating the exercise, over and over and over and over again. How many times did you practice to go back home? Did you try in one big anxious leap to move over or did you try in small steps, first visiting for five minutes only, then for six minutes, etc? Remember that your anxiety is like a small puppy, you cannot intellectually talk to a puppy and explain how it ought to be, or force it out of its behaviour. Maybe you can get some useful ideas out of watching the video and think about how you'd address the problem if you look at your anxiety as if it was as small and anxious as this little puppy in the film. When you say "I cannot do it", the "dog" wins. If you don't complete your exercise, the "dog" wins.