Re: Could this be the flu?
It is possible to get Gastric-Flu,
Which is a form of Gastritis or upset stomach. Flu like symptoms do not always affect the respiratory system.
Feeling hot/cold and shivery with aching and sore muscles are typical flu symptoms.
Keep warm and take Paracetamol or Lem-sip and drink plenty of hot/cold drinks.
Flu or upset stomach will take its course, if the upset stomach is an issue your Pharmacy can give you something for that.
If no improvement in ten days it would be wise to see your Dr.
Wishing you well, Solofelix.