Hello,
I think that the lowering of temperature in your case can be due to either antipyretics or due to exposure to cold.Pls do not take any antipyretic till you consult a doctor.Wear some warm clothes and cover yourself up properly and drink some hot drinks.As far as your fever,headache and sore throat is concerned I feel that you need to rule out strep sore throat and pharyngitis and also get yourself a course of antibiotics.Pls consult a physician immediately.
Hope it helps.Take care and pls do keep me posted on how you are doing or if you have any additional queries.Kind regards.
it foster again and ive had a really bad headace too