Most probably both....The heavy headedness is due to sinusitis, the photophobia due to migraine, the intensity is due to both coming together.
Next Steps
Have your ENT doctor prescribe you a CT scan of your nose, ears and mastoids in coronal view. This will give the doctor an inkling on the extent of the sinusitis and on how to manage it. Treating the sinusitis will automatically decrease the frequency and intensity of the headaches.