I do not know what to do about my bulimia?

It started over a year ago when I puked (not on purpose btw) after eating a very large meal. I noticed I felt light, free and liberated. I thought I would do it on purpose the next time I ate alot of fatty, tasty food so I wouldn't gain weight. Before I knew it, I had started binging and purging on a regular basis. Now I do it every day, maybe even more than once a day. I know that I am damaging myself; there are bruises and calluses on my hands and fingers from going down my throat so often. They are red and sore. Also, I can sometimes feel pain in my intestines, stomach, chest, and general pain after purging. I can literally feel my body deteriorating and calling out for help, but my mind does not work that way. Every time I binge, I think, "this is the last time. tomorrow i will just eat healthily and never purge again." Tomorrow never comes. It is an endless cycle. I am 16 years old. Tell me how to take steps to help myself; nobody around me really knows that I do this