Problem: John has obsessive and intrusive thoughts that irritate him and cause him bitternes on a daily basis. Thoughts such as how people will "get on with their lives" and forget about him. Examples being former relationships and failing a class. It is his belief that anyone who does not love him is an enemy because if they do not love him, they do not value his life.
What could be the possible mental disorder or cognitive fallacy? What are possible treatments?