Congratulation for getting through those "days in hell". As you know opiate withdrawal is no picnic. Now is the time to be on guard though. I think this is true for any substance. You start becoming bored and those old thoughts start coming back. Using starts to appear to be a rational decision after a while.
I think it's wonderful that you've gotten through the withdrawal, contacted NA and have a hotline to call. It sounds like you have a plan. It's not easy and it's a long haul, but it CAN get better.
Thank you for posting.