Medications that I am taking.....?

currently I am taking 2 mg of xanax and 30 mg of restoril to help me get to sleep at night. I also have a prescription for ambien 10mg..every night I take the xanax, restoril and also a melatonin to get to sleep, what i need to know is if it's safe to also take the ambien? Any nurses or doctors able to answer this for me please? they are all prescribed by the same doc,but it seems like a little much to me and after Heath Ledger and Britney Murphy and Corey Haim deaths all involving sleeping medications...i'm a little worried about mixing them.