What Could Cause Unusual Headache When Being On Levofloxacin?

I was on Levofloxaxin about 5 weeks ago. About 5-6 days in, I started with an unusual headache, when I would bend over. Lasted about a week, now have been left with just a nagging mild to moderate headache on the sides of my head. I don t usually get any headaches. -- I m an RN. Seemed like too long to have a persistent headache. I went to see my Oncologist today, as I had a mastectomy for breast cancer 1 & 1/2 years ago, wondering whether the headache could be at all related to cancer. He made me feel foolish for even asking, said I had DCIS cancer which would not spread like that. However, I had positive breast margins that went to my chest wall, so it always leaves me a nagging thought, if you get a weird symptom like this now. -- I will see my Primary Care tomorrow, to ask what he thinks, such as could it just be a continued reaction from Levaquin? I am 60 years old, and from what I now read, headaches seem more common in older females like me, with Levaquin.