Hello and hope you are doing well.
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. Consult your primary care physician who will do blood tests and take a throat swab to determine the cause and prescribe appropriate medications.
The cracks and holes on the tongue could be canker sores. It is very painful and can occur due to the throat infection. Apply chlorhexidine gel or any other oral antiseptic gel you can find twice daily on your mouth ulcers and leave it on for 2 mins and then do warm salt water gargles. Drink or eat half hour after application. Take OTC multivitamins rich in riboflavin to counter the mouth ulcers.
Hope this helped and do keep us posted.