@pontiac - have you had evaluation as to why you are still hypoglycemic post Whipple? I had the same experience after my Whipple and still had insulinomas in my pancreas - the same after my distal pancreatectomy and splenectomy. I continue to have hypoglycemia, however, I know it is because I still have insulinomas that were too small to locate during both surgeries.
I have not had the experience of having issues when I lay flat. My blood sugar will drop rapidly, however - mostly after meals and with exercise. I find glucose tablets helpful for episodes.
Best wishes!