What Causes Sharp Abdominal Pains Along With Green Discharge?

I'm having sharp pains in my lower abdomin. It moves from left to right and vice versa. I recently started having discharge (a light brown almost green color). I'm currently on ortho tri-cyclen lo (I just started 3 weeks ago). I took a pregnancy test, and it came out negative. My current temperature is at 94.4 degrees F.