What Causes Smelly Discharge From Belly Button?

Hi im a male, 22 yrs old. 5'6.. 77kg. On the Day before yesterday i woke up in the morning with a pain in my belly button the pain gets worse every time i bend down and move side ways etc... (every time the ab muscles contract) yesterday i noticed a smelly discharge from my belly button it had some white stuff also.. It there today as well but its a clear fluid... im totally clueless of wt this is.. need help!!!