Benedryl or namely Diphenhydramine(the chemical name) can give you a feeling of euphoria. It is not safe to take in large amounts and should not be used in this manner. but if you are going to BE VERY CAREFUL! 25-50 mgs is the normal dose. if you take more than that you could go into respiratory or cardiac arrest.
Insulin deficiency (symptom description): For a medical symptom description of 'Insulin deficiency', the following symptom information may be relevant to the symptoms: Diabetes-like symptoms (type of symptom). However, note that other causes of the symptom 'Insulin deficiency' may be possible.
How insulin affects blood sugar. Insulin is a hormone made naturally in the pancreas that helps move sugar into the cells of your body. Your cells use the sugar as fuel to make energy. Without enough insulin, sugar stays in your bloodstream, raising your blood sugar. High blood sugar, or hyperglycemia, can lead to the signs and symptoms of diabetes: Feeling extreme thirst or hunger.