Did you happen to eat an unusually fatty or acidic meal in the last few days? Without a gallbladder to gather and concentrate bile released by the liver, its possible the liver released a lot of bile, for more than you could handle without quickly getting rid of it. I know quite a few people who have had gallbladder surgery who must be very careful of what they eat because of problems with diarrhea or a sudden need to vomit. I don't know that this is the reason, but it might help to review your diet and see if a pattern develops of foods that you cannot tolerate.
If you are interested in flushing read posts made by Flowerchild59, she has given a great account of flushing without a gallbladder.