What you have to do is just take one step at a time. Make small changes. If you lose focus, there is the rest of the day. You don't even have to wait until tomorrow. You must have reasons for wanting to be healthy. Don't lose sight of those. Don't be mad at yourself, just be willing to change yourself and how you view the world. You can do this, even with all the obstacles that life gives. Have a little faith in yourself.