I woke up this morning and now my eye is swollen what could it be?

Acute swollen eye: You could have a sty, conjunctivitis, an obstructed tear duct, or a serious lid infection. If you have diabetes, you could have another kind of infection, like a fungus.

Many things!: There are too many possibilities to list here, including viral or bacterial infection, allergy, or autoimmune problems. Signs of a really serious problem include: the vision in that eye is now worse, or you see double when both eyes are open. If you wear contact lenses, take them out. If the swelling improves today, then monitor it yourself. If no improvement, see an ophthalmologist this week.