If you don't have a fireplace, but still want to hang stockings and decorate a mantel, you can craft one out of cardboard! Using cardboard display boards (ones students use for science projects), you can build a realistic (and lightweight) fireplace.
It will hurt. It will take time. It will require willpower. You will need to make healthy decisions. It requires sacrifice. You will need to push your body to its max. There will be temptation. But, I promise you, when you reach your goal, it's worth it.