Hello and welcome to justanswer,
Do you have difficulty in swalloing?Are you suffering from stress or anxiety?
Are you taking any medications? Any past medical illness?
Please describe your symptoms in details.
Well , without clinical examination and detailed history, i may not pin point the cause . But in your case there are several possibiltes like-Thyroid gland deficiencies,Emotional upset, nervousness. One possibilty is also of Anorexia nervosa. This disease anorexia nervosa, usually occurs in young persons, and have symptoms similar to you.
Also , as you are not taking meals,and fluids, it can lead to dehydration, and worsen the condition. You may be requiring a complete physical checkup from doctor along with tests like -Thyroid function tests etc..My advice is that you should be seen by doctor soon.