Dear 16-year-old self, You are beautiful as you are, and you will get better with age. As you build muscle and your curves fill out, your weight will redistribute itself. Building a personal style will get easier, so dress to your shape.
Your heart may be broken now, but you are not. Over the next few years, you will love more deeply than you think possible. Friends are going to cycle through your life and some will leave it for good. Though it's a cliche, it's a cliche for a reason.
The work you're doing now is worth it. Right now, you're learning how to write and how to write in very short form on social media. You'll make it out of high school before Facebook gets so creepy you can't start over elsewhere. You'll learn how to start over closer to home, and you'll form a community there.
Best of all, it gets better. People share your sense of humor and taste in music. In a couple years, you'll be interviewing the bands you love now. Don't limit yourself to one career possibility and try everything when you have the chance.
It may be self-serving for me to tell you to live long and well, but I'll do it anyways. Love you.