What Causes Excessive Daytime Sleepiness?

Lately I ve been waking up and finding that I stay very sleepy during the whole day. I am taking temazepam 30mg every night along with advil sinus otc and Naproxen for back pain. I m 64 yrs. old and take lots of supplements (vitamins, prilosec). This has been going on for weeks and not sure why I feel so sleepy all the time.