abg,

Sounds like your in a cycle of destruction. Eating disorders are very vicious. We are here to help. Welcome to the forum. One thing that helps is stepping out of secrecy.
Tell a friend, a family member, a pastor, a mentor.
Ask them to support and encourage you. Maybe you can call them when you are tempted to either not eat or purge.

The other big helper in my life has been therapy. Find a good therapist. Interview them. Choose one you feel comfortable with.

For me the last thing that has helped is staying attached to my faith. There is hope for you. There is nothing that love can't conquer. Your life has meaning!

Feel free to pm.