It could most probably be tonsillitis and a
throat infection.
Throat pain, difficulty swallowing, fever, scratchiness in the
throat, post nasal drip, malaise and loss of appetite are symptoms of tonsillitis. It can be caused by bacteria like streptococcus or it could be a viral infection. Bacterial infections need antibiotics. Taking the antibiotic for the required amount of days may help to clear the infection. Steam inhalations and salt water gargles can help.