WHY AM I ALWAYS HUNGRY!?

I am always hungry! No matter how much I eat, my body feels like it still wants to eat more food. I eat three meals a day, plus a healthy snack. I drink plenty of water, I'm always getting excercise. I live a healthy lifestyle. In spite of that, my appetite is extremely high. One time, after going for a walk I got so hungry to the point when I started to feel sick.

Now, I did speak to my doctor about this. He said that I have a high metabolism, so I burn off food easily. But my point is, I don't get full at all! Nothing that I eat fills me up. Pleae, I need advice! I need help! I am desperate for actual advice and no negative comments, please! You will be deleted.

I find it so hard to concentrate on other things that are not related to food. I am a pianist, composer, singer-songwriter. I am also a music director at my local church. I am keeping myself busy. However, when my stomach is constantly rumbling I find it so hard to focus on my work. When I'm writing a composition, I start for the first few minuts but then i'm so hungry and irritable that I can't focus on my composition anymore. And every time I work out or go for a walk it just makes it even worse. I feel like I can't do anything!!!!