Hi. I was having some knee pain and I went to the dr (family) yesterday. He sent me for x-rays and just thought it was oesteoarthritis. He prescribed some anti- inflammatory medicine. Today I was trying to do some walking exercise and something in the back of my knee popped. I could barely stand up or put weight on my leg. Luckily I was able to get to my car and get home. I called the Dr but did not hear from him. It still hurts like crazy and I can t straightenit or bend I. Should I go to the ER? And is tomorrow morning alright?