Most people recover from mononucleosis within two weeks. So complete bed rest with a gradual return to normal activity is required . Because the spleen, is often enlarged , it s at a greater risk of being ruptured. Contact sports such as football and soccer should be avoided at least for several weeks. Your doctor can clear you for a return to contact sports. dark urine occurs in liver disease. some times tonsils may get infected with bacteria,which can be confirmed by throat swab, in that case she may require antibiotics.for breathing difficulty steroids are prescribed.It is better you consult your physician immediately who will examine her physically and do tests like throat swab,blood work and urine work and can plan the line of management. you need to give her easily digested diet like idly,bread,butter milk,tender coconut water,hot soups,fresh fruits and veg and avoid oils and spicy food and junk like pizzas.