With the small amount of initial information provided I can only speculate, but I will try to answer as best as I can.
For many people training six days a week is too much volume to recover from in regards to putting on muscle tissue. On top of that, intensity is another factor to consider - has there been adequate stimulus to force growth? Doing movements in the gym with no planned progression is another. Are you getting better in the gym at the exercises you've selected? Are you eating enough for the amount of energy you're expending daily? Some things to consider.
OP, with the information you've provided I'd suggest reducing your weekly training volume. Try four days a week and see what happens. Be more selective with the exercises you choose, take the sets further, stick to them for a good couple months and run them to the ground.
Regardless if you're natural or enhanced, anyone can make the scale go up if you're consuming enough calories to facilitate growth. It's probable you're not eating enough my friend.
TL;DR: Lower your overall training volume and increase your calories. Good luck!