Thank you for writing.
We cannot say if your increased diarrhea is due to your recent surgery or due to something else, like the gallbladder, pancreas or liver. Back pain could indicate a kidney problem. But since you've had diarrhea since your colon surgery, there is a good chance it's connected. It sounds like you are dehydrated - it's vital that you increase your fluid intake = both water and something that contains electrolytes, like Gatorade.
Due to the fact that your symptoms have increased rather dramatically, we advise you not to wait until the 10th to see your doctor. Please call you doctor asap. Please keep us posted and we wish you the best.