I wish you lots of inner strength, and ample unseen support. Enjoy things like breathing deeply when the air is good, and when it's not, imagining it is!! :-) If you can, buy yourself some good-smelling flowers, to have in your home. I also like the smell of oranges and tangerines--(and when I water fast I still prepare food for my companion, so I can enjoy simply the good scents), but some people would find any food around to be difficult.
If you feel low one day, remember that a low is the body dealing with some important level of house-cleaning, and it will be followed by an upswing, AND these layers will progressively fall away. Occasionally on a WF, it can help to take a bath with some good Himalayan sea salt (the pink stuff). It can ease some of the rough patches, with the absorbable minerals, and the cleansing effect of the salt.
But don't court trouble, or worry. All in all, it should be fine. Take it gently, and don't write anything in stone.
It really helps to put your mind in a state where you 'pretend' that everyone is truly a kind of angel in disguise. (use whatever words work for you. This "pretending" bit by bit becomes real and genuine.) This way, you feel actually blessed by every interaction, no matter what form or shape it takes, and you become a sort of literal blessing to others. This means you will look forward to opportunities to see this holy aspect of yourself and others!!! On a water fast, you can enjoy† *eating from another place*, so to speak. It's really quite marvelous. Forgive yourself, every time you take a sip of water, for whatever you feel weighed down by. (and forgive others, of course, whenever old memories surface). As Vidda says, we all have stuff to let go of... The WF is a great opportunity, and a luxury for us, who can decide to/choose to forego food.