Hard to comment if your training is working if this is not filled out.
why one bodypart 1x per wk? I see it all the time in my gym - and only ever a select few grow with it (muscle) - you can get stronger, but most tend not to grow. 2-3 x per wk per body part is what Most tend to grow with.
Rest periods - Legs will be slow to respond with 3min recoverys. You need to fatigue the muscles, and 3min is letting them fully recover between sets, sure its hard, but damn, its supposed to be
also - If you want to add muscles, carbs perhaps need to be higher? Keeping them low will help keep you lean, will be hard to gain size though