If you wear contacts I would say that you have an infection of the lining of your eye and it needs attention. You can get this infection without wearing contacts by getting bacteria in your eye ... I would go to eye doctor and rule out infection of the cornea and if it is this they have a drop that will immediately start healing your eye. had this one time in my life and never want it again.
This really sounds like you have conjunctivitis. this is highly catchable.
You need to see your doctor to get some antibiotics this would about a 7 day lot. you will need to finish the whole lot to make suree it keeps away.
If you can't get into your doctor within the next day, make sure you wash your both eyes with a wet warm tea bag washing from the inside of the eye out to the side of your head. and make sure you wash your hands before and after you touch your eyes. also make sure oyu wash your pillow case as you may catch it again if you don't wash it.
I wish you all th best and let me know what the doctor says. :)