Hi
Welcome to the MedHelp forum!
If you have headache, dizziness and increased sensitivity to light then it could be due to migraine, retinal migraine, ophthalmic migraine, magnesium deficiency, infectious mononucleosis (if you have a recent history of flu like symptoms), chronic fatigue syndrome, hangover, side effects of certain drugs etc.
Please consult your PCP for primary examination followed by proper referral. You need to consult an eye specialist and a neurologist. Take care!
Do you ever suffer from migraines as it sounds like it could be that. If not it is worth getting your blood pressure checked.
Hope you find out what it is soon.