HELP&QUESTION "all-or-nothing" attitude

I'M GOING CRAZY WIH MY BEHAVIOR. i know it's so irritating to be this way but i can't help it. i don't wanna get into my story...just wanna know if there are other girls like me?! i'm either 'fasting' or eating like a maniac. i think heck if i eat a cookie i might as well get the binge over with and start new next day....it's been a month and i'm still doing this and putting off the stupid fast. i can't purge anymore too. and i just keep gaining. i hate myself for doing this. how can i actually motivate myself to start the damn fast for 45 days?