Sorry to hear you've had so much trouble. On a Water Fast you don't need to do enemas, the body takes care of it's own while fasting and doesn't need any help. It's quite possible that there is nothing in there to clean out and if you've added anything harsh to the water- even just salt or soap- that it was enough to scour the flesh in there and draw blood.
The body will clean the colon just fine as I said. It will also make repairs and replace linings where needed while fasting. In places like the colon which are in almost constant use the linings rarely get a chance to be replaced so the body often takes a fast as a great opportunity to do this. Again this will make the flesh in there more susceptable to breakage by whatever you are flushing it out with. Without food there is no other pressure that can be causing bleeding or hemhorroids for example, it is probably the enema that has done it. The damage sounds like it was probably superficial and won't take long to heal though.
Take care, and I hope you're discomfort doesn't last very long!