Dumping

Do you still have your gallbladder and what are you eating to cause these symptoms???

Dumping is likely to occur within the first 30-60 minutes of consuming the food since dumping is the rapid "dump" of foods into the intestine.

Several hours after eating, it's likely a reaction, or your body rejecting the food. It could also be a GI upset of bacteria.

I would recommend going on a probiotic to start off and then identify the exact food that you are eating to cause it. Avoid those foods.

Food intolerances are NOT uncommon along with transit time issues post-op.

Those are also the exact symptoms of a gall bladder attack, particularly if you have stones. Did they remove your gall bladder? It also could be IBS.