How can I feel better about myself?

I'm 16 and in tenth grade and jealousy is basically ruining my life right about now ( okay, that was an exaggeration, but it is affecting me). You see, it's not that I'm ugly, but stand me next to one of the "popular" girls at school and I look like a monster. I'm just under 5'5 and I feel like that's much too tall. All the popular girls have stupid sites with like dozens upon dozens of pics of themselves and they all have great bodies and beautiful faces and it seems so unfair. I never really did things like wear a bathing suit or fancy clothes ( I feel too ugly). I have streatch marks from when I used to be bigger ( I lost 30lbs) and serious acne scarring on my chest. I also have a weirdly shaped body. My shoulders are broad, my waist goes in, then back out, then back in at my hips, so it's like there's this huge dent. It seems so unfair when I see other girls my age just enjoying something as simple as wearing shorts or w/e. I don't even know what my question is, but I need help! Thanx, any answers would help!
P.S. Anything I can do about the acne scarring,will it fade over time and how long will it take?

Hmmm... well they usually have things that fade scars at pharmicies... and some of them really work. Another thing is you can use cover up and sometimes that will work. Just make sure to wash it a lot and use some unscented soap or something so you dont break out more. And as for the popular girls... try not to worry about them! I know its hard but theyre probably just full of themselves anyways. Try to be confident and it should help.

Try to start putting yourself in a better mindset. When you look at your self in the mirror try to think "I look beautiful" or something that will make you feel better. I know its hard to think of your self as beautiful when you don't really believe that, I don't exactly have the perfect body either, but if you keep putting the idea in your head you'll start to believe it. If that isn't working you could also join a support group, it would definately help boost your self confidence, and you'll probably end up making some new friends!

-I wish you the best of luck