Hi David,
Thanks for your query.
to give answer of your query we need a lot of answers from you-like the duration,wheather or bilateral,position,periodicity,aggravating and reliefing factors,asocciated with nausea vomiting,
photophobia,ringinging in the year,watering from eye,any vision prob etc.
After that you need a through clinical examination and if needed then some laboratory investigation.then only we can reach the diagnosis.
but for your knowledge this type of worse headache usually occurs in the following situation-migraine,tention type headache,
sinusitis,cns pathology,
temporal arteritis etc rarely may be in glaucoma,refractory error,cervical
spondylolysis etc.
so go to your doctors to diagnosis the cause of headache.
in the meantime you can take
paracetamol for relief.
thank you
DR SOURAV