Ask yourself this....were you happy when you weighed less than now? Did it benefit you in any way, honestly? One way to help your BI is to use positive affirmations. It sounds dumb but it works. Repeat positive things to yourself, even if you don't believe it right now. Maybe start by just saying "I am okay." Say it out loud, repeat it to yourself, etc.
I swear to you that you aren't fat. It's hard to accept yourself if you are insecure but this is the shape you are supposed to be, not a fragile twig. Please, for your own sake tell somebody, anybody. You can't go on living like this. You have such a long life ahead of you, so many things to do, so many people to love and to lose. Everyone deserves a chance at living their life to the fullest. Don't spoil it by not liking how you look in the mirror. People will love you for your personality if it is real love. Keep safe God's child. x