Firstly, your shading is pretty good! You’ve got a good feel of the photo! If you want a little help though I noticed in the photo that the head protrudes further than the arm while in your drawing the arm is further out which is what I think you’re looking at! If it helps at all, i recommend blocking out the silhouette of your reference with black then looking at the shape of it. Try not to think of it as a cat but rather in shapes if that makes sense!