C.E.
Have you thought about allergies?? My kids go through this every once in a while. Sometimes one eye is worse than the other. Usually they have just been exposed to something they are allergic to. I give them benadryl or children's claretin for a couple of days and it clears up. Also, if it was pink eye the eye itself would be pink and irritated. My pedi said the best way to tell pink eye from allergies is to pull the lower lid out. If the tissue is red and irritated as well as the eye than it's pink eye. If the tissue inside the lower lid is not red and irritated than it's not. I hope this helps!
Warm Regards,
C.