Final answer:
Terri is most likely experiencing anorexia nervosa, characterized by very little food intake, an obsessive fear of gaining weight, and a distorted perception of body size.
Step-by-step explanation:
Anorexia nervosa is the likely condition that Terri is experiencing based on the symptoms described. In anorexia nervosa, individuals eat very little, have an obsessive fear of gaining weight, and have a distorted perception of their body size. They are often dangerously underweight and can develop serious health problems if left untreated. Examples of these health problems include malnutrition, loss of body fluid, and vitamin and mineral deficiencies.