There's absolutely no way a natural will lose all of their gains if they skip the gym for a month, unless you're doing short periods of going to the gym, then n

There's absolutely no way a natural will lose all of their gains if they skip the gym for a month, unless you're doing short periods of going to the gym, then not going to the gym (say month on, month off), then at that point you're not really losing muscle, there was not much muscle to begin with, your muscle just became depleted instead, two other explanations could be either being seriously ill, or simply severely undereating for the period of that month to the point that your body cannibalizes itself.