is a 10 day headache normal

I've had a headache, one sided, for about 10 days straight.  I've been to the doctors before, they've all said tension headache, I had a cat scan in fall of 2006 which was clear, lately I feel like i've had some lightheadedness, a little dizzines.  I've never vomitted while having a headache but sometimes I think I may be having some nasuea.  I had pre diabetic numbers about a year ago but that number has come down, my recent random glcuose was a 109.  Could blood sugar have anything to do with the headaches/dizziness.  I admit my job is stressful and I'm recentlly married.  Is it okay to be taking pain relievers for 10 days in a row?