As the saying goes “it takes 4 weeks for you to notice your body changing, 8 weeks for your friends to notice, and 12 weeks for the rest of the world to notice” Don’t give up! You’re on your way, 15 pounds in 4 weeks is definitely progress.
I heard that the body prioritizes where the fat comes from that it burns - first the liver then the pancreas because you need to remove the fat from those organs for them to operate effectively. You won’t see that weight loss, just measure it on the scale.
Once your liver is clear, then it will start taking belly fat. So the extra (more important) benefit of your weight loss is that you are getting healthier, even if you don’t notice it at first.