IBS or not. Is this ibs?

I've been having a constant Problem with stomach upset. Some days I have to go multiple times before u leave the house and the stomach feels tender and bloated. Some days I'm perfectly fine. Facing this since a year. I've tried rifagut, multivitamins, lactobacilli, probiotics, stopping meat , proteins, grains. Nothing seemed to rid me of the problem completely. I feel very tired when the episode happens. Sometimes after meals I get severe pain in the stomach which I can tell are gasses formed in the upper abdomen. I am a dentist and I generally work siting all day. Is this IBS? Blood tests , sonography have ruled out any pathology. Do u recommend an endoscopy. I was told it's stress related, unfortunately I have a tendency to take stress which I'm trying to combat with yoga and exercise.