I went inpatient not for anorexia but for bulimia 5 1/2 years ago. It was not my decision; I was 17 at the time and my parents made the decision and I fought it every step of the way. I now see that my lack of influence was a blessing in disguise. I was so caught up in my addiction, depressed, and ashamed that I felt like hiding rather than reaching out for help.
Going to the treatment center permitted me to be happy again and be able to focus on other things. All that energy that was being devoted to the bulimia - mentally and physically - became available to me to do with as I chose. I wish you the best; you can find freedom from anorexia, even if that means reaching out for some extra support.