Sensitivity to light and pain can be a sign of corneal involvement. Sleeping in contacts can cause various problems even if they ARE extended wear lenses. I would recommend seeing an Optometrist VS an Ophthalmologist though since it is a common condition and can be treated by either (on average an OD is much cheaper that an MD and BOTH can bill your health insurance for a medical diagnosis). A simple fluorecene dye staining can show an abrasion or ulcer of the cornea. If it is a viral conjunctivitis (most people call it pink eye) it just needs to run it's course, however, these don't usually cause light sensitivity. Make sure you do NOT continue wearing the contact lenses until it is healed and make sure you dispose of the ones you were wearing (if they are disposable soft lenses that is). If it is viral, they are contaminated and will continue to keep the eye infected.
I would see an opthamologist, your eyesight is too important to play with, they will be able to tell you exactly what is taking place.
I recommend that today, you call your opthamologist and describe what you did here and see if they want to see you right away for this! They would be the one to properly diagnose you.