My psychiatrist prescribed me quetiapine to help with falling asleep about 6 months ago and after awhile I didn't really like the way it made me feel so I stopped taking it. 

2 days ago I was feeling horrible so I took 75mg to knock me out and it was quite nice. I woke up like a different person.

And yesterday when I took 25mg I felt like it had no effect.

Is it even healthy to take quetiapine for sleep for a longer period?