You are describing classic symptoms of migrainous headache. This kind of headache usually only affects one side and can be associated with blurred or unusual vision changes, numbness, tingling, nausea, avoidance of loud noise or bright lights. CT will be negative. It also often lingers for most of the day and sometimes for multiple days. Common medications like ibuprofen, acetaminophen, naproxen, Excedrin, and even coffee have proven usefull in aborting these headaches. Sometimes people need migraine specific medications, like Imitrex, Zomig, or Maxalt. People that have more than three per month may require preventative therapy with a daily medication like Topamax, or propanolol. Often there are triggers for migraines, like nitrates, cured meats, chocolate, and many others. Good luck.