Based on the information given this compulsive overthinking is called: Rumination.
Rumination can be defined as the act of thinking repeatedly or continuously over life event or life situation.
Rumination can lead lead to mental health disorder called depression as well as anxiety and can affect the way a person think due to their continuous ruminating.
It can as well lead to emotional distress as the person may begin to have negative mood as well as unhappy which in turn can lead them to begin to isolate themselves from other people which is a sign of depression.
Inconclusion this compulsive overthinking is called: Rumination.
