The best way to try to stay on top of your workout plans is to schedule your workouts!
When you start to plan your work week, also play your workout week. Figure out what days and times work best for you to work out that week. Also, when you plan the days and times of your workout go ahead and plan out what you want to do during your workout that day! This will allow you to know exactly what needs to get some when you hit the gym on your workout days. This will also allow you to keep track of what you have been doing in the gym and to help you track your health and fitness progress.