Obviously you cant completely rely on a quiz, however I reckon this one is much more reliable than most. If I were you I would look at the areas of concern and think carefully about them and wether they could indeed be problems. Any areas you recognise as an issue should then be discussed with a professional. It might also be worth discussing your scores with a friend, as I scored highly for EDs and didnt think I had an issue with thta at all however after talking to a few close friends it turns out that they all think I am sufferering from severe bulimia and have urged me to speak to my social worker about it.
I would also try and work on the areas of concern and then take the test again at a later date, from what I've heard it can reduce quite dramatically.
Hope this helps.
-Snowy