Sleepless nights

I'm 16 and find myself sleeping very late, not out of choice as I'm actually always tired and stuff but I'm too scared to sleep. I have nightmares every single night no matter what and they're always stuff that's either happened or is very possible . I suffer from panic attacks which seemed to be amplified if I sleep at a normal time because the nightmares are worse. Almost like I give my brain more time to think up something. 5am-10:30 is my current pattern. I don't know how to stop with the nightmares :/ last night terrified me. I heard a man talking like in my ear as I was drifting so I just stayed awake for hours. Sometimes I hear voices but this one was really vivid.. What to do??..