Low Blood Sugar & Low Insulin Leval

My glucose levals have been falling down into the low 40's and 50's, my insulin leval has fallen down under 2. I get clammy, shakes, confusion, visual difficulities, numbness of the tongue, cheek and very tired. I had a gastric bypass 2 years ago, I had no issues with my sugar until I lost all my weight. My gastric doctor is admitting me into the hospital on monday for 3 days. Can anyone tell me what I can expect the testing will be like? Has anyone else had low blood sugar and low insulin levals, if so, what could this mean for me? Thank you