I'm trying to gain all my fat back
When you lose body fat, you lose in the opposite order of where you were gaining. In other words, people that are overweight usually add fat on the back of their neck because it's the last place fat was deposited. When they start losing weight, the first place it is noticeable is on the back of their neck. The first place you can notice a difference with me is in my face. My opinion is that once the rest of your body loses fat, your face is more in proportion to your body and it won't look so gaunt.
Hi,
Assuming you have no systemic disease, it appears you have over exercised with out adequate consideration for your food intake. Consult a dietitian and match your nutrient intake with the level of exercising. If however, it does not help, go for an overall health check up to find out the cause for the wasting of the muscles.
Solace