Lots of people start to experience these things at that age.My nieces have rapid mood shifts thru out the day.They are 12,15 &17.The youngest and the oldest shift rapidly in much the way you describe.It COULD very well be hormones gone mad(which is what I pray for)My point is,If its disrupting your life and way too much to handle,then yes,seek help.If its not,why fix it if it aint broke? Do you always like kidding around the way you do with the slapping and jumping, Or do you hate it?