Chronic fatigue syndrome, ophthalmic migraine, refractive errors of the eye, sleep disturbances (despite your feeling sleepy), hypothyroidism, temporal arteritis, pinched
trigeminal nerve (
trigeminal neuralgia) are a few possibilities.
Since I cannot examine you and know other related conditions you may be having, nor is a detailed history possible on net, I have listed the various possibilities that should be looked into.