I think i'm addicted to codine. i've been taking it for 8months but now it doesn't seem to be working. what should i do?

Depends: There is a difference between addiction and physical dependence. Daily opiate use can lead to tolerance which you describe, and withdrawal if discontinued. Addiction is characterized by a group of behaviors, one of which is continued use despite adverse consequences. If you want to discontinue the codeine, the best way is tapering the dose over several weeks.