During treatment it's quite common to doubt the possibility of recovery. While you will encounter folks that have gone through rehab and recovered, you doubt your own ability in doing so. The best way to deal with this matter is not to think too far ahead. Rather take things one day at a time, know that you will have days that you will stumble. But also know that you also have days ahead of you where you will be able to get back on track. Rome wasn't built in a day, and the same is true for those undergoing treatment. It's a long process, don't lose hope and stay the course.