For the last two days i've had a headache and pain behind my eyes. my eyes feel as though there's fluid or pressure behind them. is this a migraine?

Sinus infection: Sinus infection can cause frontal headaches, pressure behind eyes, nasal congestion and post nasal drip. Migraine can cause similar symptoms but usually have associated nause, photophobia, throbbing pain.

Headache: Your description sounds like sinus pressure or a sinus-related headache. Other types of headaches can cause similar symptoms so i would recommend seeing an eye and regular doctor to determine to exact etiology and initiate the appropriate treatment.

Possibly: Sinus headache comes to mind, first, but migraine cannot be ruled out with the information you've provided, nor can other causes such as other infection, eye strain, or cranial bone dysfunction or certain other musculoskeletal causes. A visit to your doctor with a good history and physical, including osteopathic hands-on exam could help elucidate the cause so that proper treatment can be initiated.