Dear friend, there could be a number of reasons. I suggest you to use some artificial tears first. If you got dry eye, you can try these solutions: the first one is the visine; the second one is to use cool cloth over your eyes for a few minutes; the third one is place cucumber slices on the eyes. Or you can sleep more, usually this might be the common cause of your problem. if your situation is very serious, you may need to consult your doctors for help.
Consult with your ophthalmologist if your symptom persists. I think you should have a thorough eye examination. Based on the underlying cause, your ophthalmologist can recommend medications. Medications may include ointment, antibiotic eye drops or saline rinses or artificial tears. If it is not very serious, you can use home Remedies to relieve your symptom. I heard that natural herbal and holistic remedies are highly effective medications in cure discomfort and eye irritation.