What Causes Short Sleep At Night Even After Having Alzam And Zolpidem?

I am currently on alzam and Zolphidem. Struggle to sleep at night. Drinking my Alzam at about 7pm and my Zolphidem at 10pm. It take abou 2 hours before I start feeling drowzy or sleepy. Only sleep for about 2 hours a night and feeling very tired in the mornings. I would like to know why I sleep so little at night. Sometimes not at all!