Hey, I completely understand not having the money to see your family doctor, but you need to see someone.
Here's a couple things to keep in mind:
if it gets really bad, go to the hospital. They have to treat you, even if you have no insurance, and no money. And
every hospital will work with you financially, I know people who after going to the hospital and getting a bill later in the mail, called the hospital, and the balance was dropped (there was a lot of paperwork, and proving your income and such, but it is possible)
the other thing you can try is a clinic. A lot of clinics are associated with hospitals, and the other way around (hospitals associated with clinics) some clinics offer free medical treatment to qualifying patients, and for others they work on a sliding scale. But there are clinics everywhere, in every city. So you just have to look.
Hmm... I just realized something... Are you in the us? Cus if not, this info may not help at all. I don't know how healthcare works in other countries... Just here.
At any rate, I hope this info helps. And I hope you get help. Headaches can be nasty, and can completely prevent you from living a normal life.
~qriosity~