I Have Uncontrollable Gas That Stays With Me All Through

I have uncontrollable gas that stays with me all through out my days. Have tried over the counter meds for at least one month each, have also tried different diets. The gas pains that sneak up are excruciating pains. This has been going on for over a year now. It is very embarrassing in front of my customers at work there is just no way I can hold it in. What should I do?