Depression - Teen Support Group
Teen depression is marked by persistent sadness, discouragement, loss of self-worth, and loss of interest in usual activities. Depression can be a temporary response to many situations and stresses. Teens may be more susceptible to depression due to the normal maturation process, the stress associated with it, and conflicts with parents as they become more independent.
Unless your BodyMassIndex indicates otherwise, I guess its pretty much you convincing yourself you're overweight in which case, I suppose maybe think about seeing a therapist or councillor, eating disorders can leave behind mentality issues aswell as physical ones.