if sobriety wasn't worth it then you wouldn't see the hundreds of users on this site fighting day in and day out to regain control of their lives from the clutches of addition. If anything in your life is worth fighting for its your sobriety because without it life is empty and full of pain and sorrow.
You are not a lost cause and you can take comfort in the fact that everyone that gets sober and stays sober had the same exact feelings you are sharing now. You can do this and I can promise you that it WILL be worth it.