What Causes Abdominal Cramps And Pain In Right Lower Quadrant?

In the beginning of this month, I had what I believed to be abdominal/cramps. Those lasted for about 2 weeks until my menstrual cycle began. Once it was over, I was fine. But today I noticed that when I was walking, I had pain in my right lower quadrant and the more that I walked, the sharper the pain became. And even now, as Im sitting down typing this, I still feel the pain. Could I possibly have appendicitis? I've pressed down on the area and when I do that, its very tender.