Suggest Remedy For A Very Sharp In The Left Knee

Hi, today at work i started getting a very sharp pain in my left knee. it continued to hurt all day and still hurts. I cannot put alot of weight on my left leg and if i bend my knee it causes alot of pain. There is a little bit of swelling and if i push on my knee, it causes numbness and tingling in my foot. can you please tell me what could be causing this? thank you ~Stacy