Mood swings before labor?

The emotional break downs are getting real, 39 weeks today and I just feel like shit. I seriously feel like I'm about to start my period. I'm unbelievably cranky which I haven't been my entire pregnancy. I cryed my eyes out this morning because I was starving and wanted breakfast but I was to tired to get out of bed! I haven't acted like this during any of my pregnancy. I've had 3 days in a row of just feeling crappy, I don't know how I'm going to keep this up until baby gets here! Did anyone else notice a severe change in mood before labor started? I just don't feel myself at all.