My left eye feels sunken in and i have a swollen pocket under my eye?

Infection or sinus: Swelling under the eye is usually from an infection of the eyelids (tenderness and redness also), an allergy type problem of the eye or skin (usually itching also), orbital inflammation (pain especially with eye movement), or sinus disease. Sleeping with the head elevated and ice may help reduce the swelling. If it persists, you may need an exam to diagnosis the underlying problem.