Headache can be due to numerous reasons like migraine,unresolved sinus infection, allergies, inner ear infection or defect etc. Based on the history you have given, I am suspecting allergic reaction to dust mites. Switching on the fan inside a unclean room will recirculate the air inside room along with the dust particles settled in the room, so inhaling this dust filled air on regular basis can cause repeated sneezing,running nose, headaches. So mainly I suggest you to clean your room including the fan and if possible sleep with a window open in a clean room to have a fresh air. Coming to sinusitis-
Get plenty of rest. This will help your body fight infection and speed recovery.
Drink plenty of fluids, such as water or juice. This will help dilute mucous secretions and promote drainage. Avoid beverages that contain caffeine or alcohol, as they can be dehydrating. Drinking alcohol can also worsen the swelling of the lining of the sinuses and nose.
Moisten your sinus cavities. Drape a towel over your head as you breathe in the vapor from a bowl of hot water. Keep the vapor directed toward your face. Or take a hot shower, breathing in the warm, moist air. This will help ease pain and help mucus drain.
Apply warm compresses to your face. Place warm, damp towels around your nose, cheeks and eyes to ease facial pain.
Rinse out your nasal passages. Use a specially designed squeeze bottle (Sinus Rinse, others) or neti pot to rinse your nasal passages. This home remedy, called nasal lavage, can help clear your sinuses. If you make your own rinse, use water that's contaminant-free — distilled, sterile, previously boiled and cooled, or filtered using a filter with an absolute pore size of 1 micron or smaller — to make up the irrigation solution. Also be sure to rinse the irrigation device after each use with contaminant-free water and leave open to air-dry.
Sleep with your head elevated. This will help your sinuses drain,reducing congestion. morning do jogging for 30-40mins and brisk walking for 15-20mins. Do breathing excercise for 15-20mins and meditation to develop stamina. Get a allergy test done to know about the things you are allergic and avoid coming in contact with such things. If you are not satisfied kindly consult a physician for further management