What Causes Cramps With Brown Discharge In Woman With Tied Tubes?

Hello, My concern is that I had my period on 6/6/2011 and lasted 7 days... On 6/18/2011 After getting out of the pool I noticed stomach cramps lower back pain and a Brown mucus discharge. I am concerned I had my tubes tied 10 yrs ago. What can be causing these symptoms? need a responce ASAP Plz.