Ok, good for having the gall bladder removed. That can cause very similar symptoms as you have described and wanted to rule that out first.
As far as the bloating goes, I see you have tried Gas-X...this contains Simethicone and will be the best thing for you to take for your bloating. As far as dosage, you can take a maximum of 480mg per day .... usual dosage for flatulence is 80-120mg's four times a day as needed. I would suggest checking the strength of the Gas-X and increasing your dosage of Gas-X (if you are not already at the Max) and see if this helps. Also, staying away from known triggers, of course for gas such as onions, cucumbers, beans, green peppers, cabbage, soft drinks (coca-cola), apples, bananas, prunes, melons, eggs, fried breads such as donuts, and pastries, artifical sweetners, and milk products. I see you use gluten free products and avoid wheat--think you might have consumed something that was not gluten-free?? (just brain storming).
In the meantime, you can use a stool softner to help facilitate the passage of stool easier and ward off future constipation problems.
Hope this helps....reply back if needed