Dear sir, it could mean many things, but i think that there shouldnt be any relation between your gallbladder
removal and these symptom. it sounds for me more like typical colon
disorder; IBD, Crohn or ulcerose colitis
, infective colitis etc. The best way to rule it out is to do colonosopy. After that you can plan further tests. Blood in stool
can also be serious sign of some benign(polyps,haemorrhoids,fissuea) as well as malignant diseases so dont be very concerned but do colonosocopy definitely.
Wish you good health,Dr. Ivan Romich