What could cause belly button leakage and bleeding, also with abdomenal pressure, blockage, affecting heart and breathing.?

Go to Emergency : I am concerned about you. Fluid and bleeding at your belly button, with additional abdominal symptoms (pressure, distension) and systemic symptoms (fast heart rate, short of breath) means you need to go to the emergency room of your hospital. Until evaluated, you have an incarcerated hernia and bowel obstruction. Don't wait.

Urachal cyst: The most common cause of belly button leakage is recent surgery, usually laparoscopic, done through the belly button. However if you haven't had surgery then it's likely a urachal cyst that is draining. Depending on it's size it can be treated in a surgeon's office with simple cauterization of the of the tissue inside the cyst that produces the fluid or it may require resection of the cyst.