In recovery, we are asked to do one of the hardest things a human being can be asked to do, in the least capable state possible. People aren't built to walk away from pleasure, so how can one find the motivation to stay clean? Do it for reasons other than yourself, especially if you don't think highly of yourself. Find motivation to change, in those you affect by your use. Use your guilt over hurting others as motivation to change, instead of as an impetus to use. Your recovery is a gift to others.