Re: Drastic decrease in performance
To expand on Scrap. Sleep and food decline or surplus are more the symptom, not the cause. In hearing what you are saying, as long as everything checks outs medically, I would say it is undoubtedly stress.
Yours is not performance stress(which is natural and good), but chronic stress, or distress. This can affect the immune system, alter testosterone and growth hormone levels, and adrenaline. The stress hormones that once worked to protect may be overproducing, which can then affect metabolism and how cells grow and repair.
I work as a Licensed Professional Counselor and can say that when the people I work with are chronically placed under continuous levels of stess, they perform poorly at work, in marriages, as parents, develop anxiety, anger, depression, and so forth.
My advice is lighten your boxing load a bit and get the other stuff in order. The fact that you are asking the question is your answer. Pushing harder is not the answer, too much is,... too much. Good luck Paolo!