Knee pain that is extremely bad!?!?

I went running today (nothing abnormal about my run, it was actually a fairly easy run). 5 minutes after my run (after stretching for cool down) my knees felt extremely tight. I did what every athlete does and put my legs on pillows with ice and took Motrin. It has been almost 9 hours (and 4 Motrins later, took 1 after running and 3 a couple hours ago) and my pain is worse. I can no longer bend my knees and my toes feel a little tight also (am trying to keep bending toes, ankles, knees to avoid them getting stiff) I can barely walk without pain. All te pain is the whole front of my knee (none in the back). Since it is 12:30 AM everyone in my house is asleep but I can not even get comfortable to sleep. What should i do? And what is the problem?