make (oneself) miserable
To cause oneself a great amount of stress, anxiety, sadness, etc. I don't understand why she keeps making herself miserable in a job she hates. She's just not interested in you romantically, Jack, so stop making yourself miserable pining over her!
make oneself miserable
to do things which cause one to be unhappy. You're just making yourself miserable by trying to do something you aren't qualified to do. I'm not making myself miserable! You're making me miserable.