You seem to be dealing with problems concerning flashbacks these friends are causing. Maybe you need to resolve the problems brought up by the flashbacks first. I certainly understand this. Two years ago I retired on disability and still can not face some memories that come back. As Justfloating stated maybe you should try steering the conversation away from school first, and then if you can not, stay away from these people. You do not need to have your self esteem battered each time you see them. Good Luck