Sleep. You probably need to sleep more than you need to crush your workouts every day. Aim for 7-8 hours nightly to ensure your body has time to recover and repair.
Increase your Non Exercise Activity Thermogenesis. (NEAT) Moving more in your daily life by walking, standing, parking farther away, taking the stairs. You can burn more calories without putting extra stress on the body (or requiring you to eat extra calories) like formal workouts do.
Eat more protein. This is a muscle building powerhouse. Eating more will stoke that metabolic fire.
Eat more. Chances are, you are under eating for what your body needs to function optimally. Our metabolism is adaptable- the more you eat the higher it is and the less you eat the lower it is. Your metabolism has NO hope on those 1200, 1000 even 900 calorie diets. 😬