Staph infection in Belly Button.

I had pain and yellow discharge in my Belly Button around one month ago so I consulted a gastroenterologist he suggested to do sonography test then I tested and found out that I have some small cavity in my Belly Button that is filled with pus so the doctor said it is very small cavity and don't need any surgery and gave me medicine and t bact ont. After few days the pain is completely gone but the pus is still coming out from Belly Button then I again consulted this time he suggested to do the pus culture and sensitivity test and I did the test and found out that I have Staph infection (Staphylococcus aureus MSSA Strain) according to the test he gave me "Trimethoprin/Sulfamethoxazole" (Bactrim d.s) Tablet this antibiotic is second most effective against Bacteria according to test now almost 7 days has passed I am taking this antibiotic but still the pus is coming out of Belly Button 😓