Supporting workouts

Curious how folks get enough in to supporting working out at the same time? I’m focusing on and tracking my protein, fiber and water and have been doing well with those, but the amount day-to-day has decreased so much I’m concerned about supporting my workouts too. I’m only at the end of week two, so maybe the fatigue will ease up? But my decrease in appetite has been intense and has been concerned as I do not want to loss my muscle.