[Arabesque- golfing girl.]

Hello and welcome to teenhelp, we are glad that you have joined. You also did a great job saying what is going on with you.

I am sorry that you are having a hard time with this right now.
You don't want to be missing you're periods no matter what is going on. And you are also young to have that happen to you. Can you try talking to the school counselor or you're parents or the school nurse and let them know about this and that you are having a hard time with food and this too. You need to tell someone about this so that you're parents can take you to the doctor to get checked out. You can say that you are having a hard time with food and now you are missing you're periods and you need help.
If it's too hard to say, then you can always write them a letter. And they can read that and then help you.

I hope that you will be ok and you can always post more when you need to. Hugs.