Janet. Has your GI looked into gastroparesis? This is neuropathy of the nerves to the stomach. lt's most commonly associated with diabetes, but can be from other causes as well.
l have a friend who is diabetic and has this and the more l thought about your symptoms, the more little bells started ringing. Ask your GI about it.
l assume, at your weight you are being monitored closely for diabetes, but as l said, it can happen for other reasons as well.