I know you trusted your school counselor.....theres nothing wrong with that.Mood swings can mean alot of things not just bp.
Bp runs in my family,I didnt think I had it because I dont get the anger like them.I too can be very "normal"and then CRASH Im depressed.My depression is as severe as my family members.....one of which is bp 1.
Maybe your not bp.....maybe its something else.Until you know for sure dont get too worked up.....you'll have plenty of time to wrap your head around it later.
In the meantime stay away from alcohol and keep a journal....over time you may see a pattern....
Good luck jordy