Have you ever had a sleep study done? There has to be a reason why you can't sleep.
Hi i know what you are going through , more or less you said my story , i had a big addiction to Zopiclone , over time very slowly came off it , then my problems increased with sleepless night's , i looked up Melatonin on the Net , i asked my Dr if i could try it out and it works for me ,
At least i do get a good nights sleep because of Melatonin , i am also on a CPAP Machine of a night with no problems , i hope this helps you , Take care ,