Hi ,Welcome to HCM ,
your Gastric problem difficult to control untill and unless you adopt healthy life style modification , 
as you underwent 
bypass surgery you need to take above all medicine  regularly , 
please take medicine in time , 
do some life style changes like 
eat bland diet , eat more of fresh fruit , fresh green leafy vegetables , 
restrict salt intake , 
avoid spicy food , 
avoid non veg and junk food , 
do not take heavy meal , 
take small frequent meals , 
stay relax , 
take proper sleep , 
avoid alcohol use if you are taking , 
avoid immediate sleep after food , 
do not use any form of tobacco , 
do 
stress relaxing yogas , 
avoid too spicy , too 
cold , too hot food , 
i think life style changes will help you lot to control your gastric problem , 
take care