If you want to stick with meats...you need more fats. Sounds like low calories if you workouts are suffering and you are losing muscle. Have as much carbs as you feel your body needs....but overdoing the carbs can be going down a road of insulin resistance and silent inflammation. As even skinny people can get diabetes and heart attacks.
Oh yeah...nothing wrong with Red Meat....in fact....you will build more muscle (and maintain it) rather than a meat like chicken that has nothing else to give but protein. Meat and eggs.....has worked for 100s of years.