Sad AGAIN

I was feeling good earlier today, but that feeling is gone and I am sad again.  I'm obsessing about my ex and I'm sad because I sure he isn't obsessing over me.  He was cruising a hook up site two weeks after we broke up.  We were still living in the same house but separated.  
Relationships have the potential to make all of your worst fears a reality.  I'm tired and I want to be done with all of this.  Damn.