Okay well being 15 you must be careful when llosing weight, because you are growing as i know many poeple have probably told you. This is an important time to eat atleast what you need for maintenance, but may i suggest if you want to tone up a little add some exercise. Join a gym, do some light weights that will really help you get toned up.
WHo knows maybe in a little time youll have guys turning heads at your new looks!
I hope this helps you out, and maybe if ya want you can pm me and ill help you further.