I have had a sinus migraine for over two weeks. antibiotics and painkillers don't seem to work. what will?

Too long: That is too long for a migraine. See the doctor to see if there is another cause, such as a sinus infection. You may have a different kind of headache in addition to your migraines.

Further workup: What we call a sinus migraine, is a patient that has typical migraine and an acute sinusitis triggers a bad headache. If you don't have typical migraine and are calling this a sinus migraine, and it happens a lot you may have severe chronic sinusitis that may need to have a ct scan of sinuses and possible endoscopic sinus surgery. Please see an ENT specialist.