Reacting to the fear of mental health worsening is no different than reacting to any other fear. The more you try to control that uncertainty, the more anxious you’ll get, the more compulsions you’ll engage in, and the more you’ll contribute to relapsing.
When you feel that uncertainty, it can be a great opportunity to practice trusting yourself. Whatever happens, you can get through it and you can keep making healthy choices. You have the skills now to take care of and improve your mental health. If you step off the path in the future, you can recognize that and then step back on the path again.