For 3 Days I'm Having What Feels Like A Shadow

For 3 days i'm having what feels like a shadow over my left eye. when i look around i can see what appears to be a film or light cloud. i can see and i have no pain and no redness. i look in the mirror and do not see anything in my eye. it feels like something is covering my eyeball. please help. i don't recall anything unusual happening to my eye.