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.
This is in contrast to diabetes mellitus type 1, in which there is an absolute lack of insulin due to breakdown of islet cells in the pancreas. The classic symptoms are excess thirst, frequent urination, and constant hunger.