
Has she aten anything that may have causes it like splinters off a bone- how much blood in her stool? Is her poo formed or runny? Maybe she caught a bug or something. I too would listen to the vet and what they told you. Can you give her yogurt at all?
Not trying to worry you but our shepherd/collie we had years ago had blood in her poo and the vet put her under to see why. The blood was more a bright red and her stool was hard- turned out she had cancer of the colon (something like that), she ended up with tumors in her bum so we were recommended to put her on metamucil to help soften her poo- she was old and the op would have been a pricey one which she may not have made it so we chose to keep her comfortable the best we could...
Do hope nothing serious and all is well- best of luck :)