I had this when I was a kid. I ended up waking up not able to open my eyes, because all the goo was sticking the eyelashes together. So, you may even need to have someone bring you a cool wash cloth every time you wake up, so you can open your eyes.
Always get a clean wash cloth each time and don't let anyone else use the washcloth. It should go in the laundry immediately after use. Unlike when you can use the same wash cloth all day long after rinsing it well and hanging it up to dry, you can't do that with conjunctivitis, also known as "pink eye".
sleep helps along with flushing your eye out with water and a WARM compress.
It could be conjunctivitis, which is an eye infection that is HIGHLY contagious. You need to have your parents or guardians take you to the doctor to get checked. Meanwhile, try not to rub your eye and be especially careful about not rubbing it and then touching the other eye or someone else's eyes. To help with the redness, swelling and itchiness, cool compresses may help - wet a washcloth with cool water and gently BLOT (don't rub) your eye. You may also find that laying down in bed resting with a cool cloth over your eye is soothing.
I hope you feel better soon!