I’m not a mental health professional, nor do I play one on T.V.. I would find one, or a good listener who you can talk about this with. On your own you could go cold turkey with e-stalking her. Perhaps block her, uninstall apps, etc. At the same time you could start building up your social network, making friends, going out, etc. Maybe you are focused on her life, because your own life is a bit empty, and by filling up your own life it will be easier to naturally become unconcerned with hers.