How Can sharp Abdominal Pain Along With Nausea Be Treated?

I have on approximately six different occasions experienced sharp abdominal pains shortly after eating, followed by bloating, nausea, gas, occasional vomiting and a feeling of lethargy. I am 64 years old and fairly healthy. These episodes usually occur at or after lunch. The one common issue is when I eat food products with wheat or seeds. Taking antacids as soon as the symptoms start has helped, if they are accessible. I take fiber drinks in the morning and my bowel movements are pretty regular.