Sleepless nights

Lately I've been tired. It's not because i'm going to bed late and waking up (even though I do that), it's because I can't sleep. I can't fall asleep till after 11pm and I wake up 1-2 times a night with nightmares. I'm not sure why it's happening but it is and has been for sometime. They are nothing like nightmares I use to have. They seem real like when I go to sleep I'm in another dimension and that everything is going wrong. That those I love are dying or i'm dying. I have tried melatonin but that has made things worse to the point of waking up every hour and half with very vivid dreams that scare me. I fear sleeping due to these dreams I've been having and am to the point where I don't know what to do anymore. I don't exactly have the money to go to the doctors to find out what's going on. If any of you know anything that I can try that might help please let me know.