Hey!
If you opt for the enemas - do it with water only. Coffee in any forms and Water Fast don't go well together. Most ppl here would tell - forgo the enemas altogether. I don't have such restriction tendency, although I'd do it not that often. I did 1 cleanse on a 8 day fast, but I had a good clean up beforehand and I did not have evacuation problems, attributable to chronic drug use.
Peeing black is kind of scary - are you sure this was not blood? Could it be tar form drug use? Be sure you do not fall, and rise slowly as to avoid dizziness.
You can do it! At the end you will feel so much better. Very important: take care to re-start a healthy Diet after the fast and keep a healthy lifestyle. Drugs numb us, they are not a solution to any problem - just a tool to postpone dealing with the problems.
Cheers,
DL