Frequent bowel movement. Eating balanced diet. Is it due to tension?

i am rajat 18 years old & 75 kg weight.....When i was in 10 th class i use to go to laterine nearly everyday in school...Then when i reached to 11th class i joint classes....Now in 12th class a similar kind of porblem started.....When i attend my 4 pm coaching classes a sudden gas start developing evryday around 5 pm....Its so embarasing to go to laterine everyday that now i have stop atending classes regulary due to this problem.....I went to a gastroetrologist few day before....He said its nothing only due to tension you develop some gas.....I had some test all were just normal.....From last month i started eating a well balanced diet ...I do my workouts on regular intervals...Though i feel far better from last few days....But still i goes atleast 3-4 times a day to laterine.....Sometimes when i am in market i had a fear of developing gas suddenly some gas develops & i have run for laterine......I really always live in such problem whenever m outside home that sudenly gas will develop & i have to run for laterine...Its really very embarasing.....!!