Sand grain like irritation in both my eyes, though there is no foreign body in them. makes me constantly rub my eyes.

Dry eye : Is most likely. Get some OTC artificial tears to use. If it doesn't help go see an eyedoc.

Coupla possibiities: You could also have an allergy or even an early infection. If you pull down your lower lid, do you see any bumps or redness? You might get some relief by using cool compresses or liquid tears, which you can keep in the refrigerator, but don't rub or you could make it worse. Don't even put your hands near your eyes except to apply tears. If eye gets pink or very red, you might be contagious.