Rehab aftercare, use it!
Many drug rehabs offer an aftercare program of some sort, usually a program that offers support of one kind or another to help you keep on track after you have completed drug rehab. Use these programs, if the opportunity presents itself. Keeping on track is as much about being strong within yourself as it is the support that you have around you – aftercare programs offer that support, and it really is priceless and has helped countless people when the real world gets hard.
Life is very hard at times, and having somewhere to go, or someone to talk to who will give you perspective is a proven method of being able to overcome triggers and stress that could lead to a relapse.
Aftercare programs differ and can offer everything from just being able to call someone to talk to when you need it, or you could be offered housing and support from others in a similar situation around you. Whatever you are offered, take advantage of it, and use it as a tool to help you stay sober, and build up a new life without addiction, but with support and possibilities.