Dic: turn in on yourself

■ turn in (up)on oneself: to become introverted.

• Over the years, she had turned in upon herself and was quiet and alone. 
• The death of his wife caused Jed to turn in on himself.

.... McGraw-Hill Dictionary of American Idioms and Phrasal Verbs 

■ to become very concerned with your own problems and stop communicating with others.

• He completely turned in on himself after his wife left him. 
• You won't be able to lump yourselves as British any more and you can turn in on yourselves.

.... Oxford Phrasal Verbs, Collins English,  

■ to start to think only about yourself and your own problems and to forget about other people and their problems

.... http://www.macmillandictionary.com/dictionary/british/turn-in-on