irregular bowel movement.. psychological, lifestyle, or depression caused to me

     I am only a 17yrs. old & freshman in college... I don't usually feel of going to the comfort room 'on-time'... instead i only do feels to do when i'm  already out of the house & most usually in school..!  And the most horrible! Where you can't stop your fart & everything!!! Cause it's really hard to do the thing when you very well know that there's no complete facilities to feed your need.
     I'm not only sure if it is called acidification or gastritis that the doctor told my mom, back when they sent me immediately to the dr.'s house on that evening after eating too many oranges/mandarin & felt like my stomach was crumpling painfully. But it was i think.. when I was still 9 to 10 yrs. old due to drinking too much soft drinks also.
     I also have my problem regarding my teeth.. I have an open bite case which make chewing real hard for me too. Which I think also affects my digestive problem.