I would be very concerned. My niece, who is also 13, is going through this exact thing right now. My sister has tried everything, but she clams up and insists it's nothing. My sister is divorced and I personally think the issues weren't dealt with well. Now they are living with my sister's boyfriend so I'm sure there are many security issues, etc. My sister finally agreed with us that it is an issue and is taking my niece to see a counselor... they are hoping she'll open up to someone objective. I should say that my niece is a straight A, honor student who excels in many extra curricular activities as well. My sister recently found out she was sneaking on the internet (even though she has been told not to because of previous MySpace issues) and has created another MS page and is talking about all the boys she's kissed, etc. I personally remember exactly what it felt like to be 13. It was such a tough age and the pressures were coming from every direction... parents, school, boys, friends, environment. I had an eating disorder for most of my life and I think that stemmed from being the one thing in my life that I could control and no one else could be involved in what I did in my "private" time. I remember the feeling of seeming cleansed when I made myself throw up and knew I was "empty"... it's all very significant of the family issues they are dealing with and their environment as well. I would look at what is happening with school, friends. How is your relationship with your child, with their siblings, etc? If you have the ability financially to take her to a counselor, I definitely would. I'd go as a family and let her go individually as well. This is serious and don't let anyone wash over it and tell you it will pass. This is my personal opinion from my own experiences and the experiences my sister is having with my 13 year old niece. Good luck and many Blessings!!