Why can’t I get tired to go to sleep? But when I need to be up I’m always tired?

Patient: I am on disability for mental illness, and I volunteer at various places during the day, but at night I seem to not be able to get tired so I can go to sleep. I play a lot of video games at home, and that may be the contributor, but I have a lot of friends that play video games and have no problem getting to sleep.It also seems that whenever I have to do something important, I can never get the energy up, my eyelids feel like anvils and I can’t keep my eyes open. I am trying melatonin and tea with milk but to no avail.