You don't need to use colonics, be careful if you do as they can take a lot of energy out of you apparently. I've personally fasted for 30 days without the need for them so it's not just opinion but also based on my experience.
Distilled water is perfect. Just make sure nothing is added to it, I've heard some commercial brands add minerals or something to them.
Tiredness and body aches are very common. Also times of great energy, nausea, headaches, skin blemishes, bad breath, cold-like symptoms, the list goes on. Whatever your body can do to aid detoxification it probably will! Many don't feel much discomfort at all but some crises can be quite distressing, we need to be prepared for all eventualities.