Explicating WHY you want to keep going to the gym a habit should help you reclaim your DAWG. It's also important to return to these reasons, especially the ones most meaningful to you if you feel your motivation waning, through the frame, "I want to go to the gym, because....." And then remind yourself of why you want to achieve it.
There are two more exercises you can do if you want to deepen your connection to yourself and your sense of meaning.
One of them is to imagine an event that takes place once you've reached a certain important goal or milestone, that you want to take place, that would be meaningful to you, writing it down in detail, including how you would feel if that event, important goal or outcome took place.
Another powerful exercise relative not only to your habit of exercise but also the meaning of your life and your deepest values, is to write down what you want people to say about you at your funeral, which is in some sense the legacy you will leave behind.
Since the four human needs are to live, love, learn, and leave a legacy, going through this exercise would be powerful for you.
I'm proud of you for writing down your 50 reasons for exercising. Bless you on your journey!