Just a thought: have you ever had a sleep study? Someone close to me had very similar symptoms, attempted suicide several times, and could sleep for days non stop.

He had a sleep study done, and the doctors found a rare form of epilepsy that prevents his brain from going into REM sleep... enough to make anyone crazy. He's treating the epilepsy, and now doesn't need psychotropic meds and has cut smoking to almost nothing. Hope this helps!