Sugar - it absolutely goes away. The thoughts that it will never go away and things will never get better is part of the addictive thinking. What you are feeling right now is just a feeling. It will pass so long as you don't use.
It was when I started feeling like you are describing that I realized what addiction really is. I would ask myself "why the hell did I stop using if this is all life has to offer?". It was terrifying to realize that just removing the drugs and counting days wasn't enough. I had to take an active role in improving my life or I would eventually use again. Going to NA/AA helped me tremendously. Outpatient was somewhat helpful for me.
You have already done a lot by admitting to yourself that you can't do it without some outside help. Good for you. My pride kept me from admitting that for a long, long time, and I put myself through absolute hell before I got to that point. Make the plans for counseling / OP and stick to it this time.
You can do this. You can get through this tough period. You can get to the point where life isn't just surviving, but actually living.