For The Last Several Months Now My Stomach Gets Very

For the last several months now my stomach gets very bloated if I don't eat when I'm a little hungry, it's so bad that I feel like I'm constantly eating (which has made me gain weight) some days it's so bad I have unbutton jeans.. My Doc.. Thinks it's the food I eat but like I told him it can't be because it does if I'm not eating and after I eat 30 mins or so I have gas for the rest of the night. Should I go see a different doctor maybe GI Doctor?