What Is Causing The Brown Gooey Discharge After Period?

Hello, it has been 12 days since my period ended and I am recently getting a brown gooey discharge 2-3 times throughout the day. After urinating I find a light brown color although no discharge is attached. This has been happening for 2 full days. I am now starting to get a discomfort in nmy kidneys. Can you tell me what could be causing this discharge? I am 25yrs old, 5,7 and 110 pounds. I don't have any past health issues.