you are probably right that your junior status ultimately did you in.
my thought is definitely consider informal. also, contact with panhellenic about the apparent discrepency so perhaps you can get back in the snap bid race, or if not, at least no one else will get incorrect advice in the future.
it sounds like you have already got a solid circle of friends. it sounds like your classes are fine. now just relax and enjoy life. if things click, terrific. if not, you keep your head up and think about doing other stuff.
lol
feel better