I JUST HAD AA COLON RESECTION BUT AM HAVING PROBLEMS

I JUST HAD AA COLON RESECTION BUT AM HAVING PROBLEMS WITH DIARHEA AND CONSTIPATION AND SOME VOMITING. IT;S BEEN 7 WEEKS OUT NOW AND AM WONDERING ABOUT THE GALL BLADDER. I HAD AN ULTRASOUND OF THE GALL BLADDER AND IT SHOWED SIGNIFICANT FAT TISSUE BUILD-UP AROUND IT. MY GASTROENTEROLOGIST WANTS TO DO A TEST TO SEE IF IT'S FUNCTIONING CORRECTLY. WHAT EXACTLY IS THE FUNCTION OF THE GALL BLADDER AND WHAT HAPPENS IF IT'S REMOVED?