Ouch!

This is how my right eye feels today. And I have no idea how it happened. :(
Last night, I was sitting on the end of my bed reading with the kitty sitting beside me, when it suddenly felt like something had gotten in my eye. I assumed it was an eyelash, because I often have one of my thick eyelashes falling into my eye and then struggle to get it out. This time, I couldn't find an eyelash, but had a hard time opening my eye.
In the end, the outer side of my right eye still hurts. It almost...