You ARE enough. Don't get overwhelmed. It's easy to let happen. Just know that even if all you manage to accomplish today is brushing your teeth... THAT is enough. Because instead of using, you brushed your teeth! I'm telling you, I had days (sometimes many in a row) where even that seemed an impossible feat. Coming off of opiates creates incredible depression for me, and i suffered with some of the same types of thoughts you're expressing. I don't know the answers, but I hope that knowing others have been in your shoes helps relieve some of your anxiety. Because it gets better. I never thought I could or would feel better, but after the w/d sx went away and I got on a low dose of antidepressants... it was like a curtain lifted and I felt my life again. Sometimes things still suck, sometimes my energy is still in the dumps, sometimes I still cry or hate my life. But those times are fewer and farther between, and even though I spent a LONG time trying NOT to feel feelings, I'm grateful to feel them now- both good and bad.
Use the alone time to be productive in your recovery. Journal. Go to meetings. Chat on the forums with others in recovery. Read literature on addiction/recovery (I've found doing that is inspiring!)