What could cause a mild dull headache accompanied with visual snow, irritability, depressive mood, seeing shadow people and somewhat similar hallucinations, sensitivity to light (can only keep my eyes slightly open during the day when I m outside)? I ve had this before for 2 weeks until it suddenly all disappeared at once. This has slowly started coming back about 2 weeks ago when I bumped my head into the wall. Not sure if related. Solved: Went to doctor, he found out the cause was sinusitis.