What on earth is wrong with her?

As a vegetarian, you might have a nutritional deficiency that you are not satisfying with your current diet. 2000 Calories is a lot of calories if you are not exercising. Try introducing a variety of beans/ Legumes and nuts to help increase your protein intake. If you are not exercising, your digestion might be slowing down. Drink plenty of clear fluids and try whole grains for breakfast like oatmeal and have high fiber snacks like carats, celery, apples, plums and so on... The key to good nutrition is to mix it up and make sure you have enough of the vegetarian foods that high enough in protein to satisfy your bodies needs.