Your description is suggestive of probable virus fever
Getting examined is the best option!
You might have heard the local saying, "Treated cold
lasts fortnight; untreated for fourteen days" - this implies, there are no specific drugs for most of them... They are often due to viruses and generally the cure is spontaneous.
Take symptomatic measures - like paracetamol
for fever; decongestant for nose; lozenges for throat; cough
syrup - all are available Over The Counter.
If you have any doubt or if the fever is prolonged, the phlegm has green or yellow colour; breathless and so on- you must see a doctor immediately.