it's highly recommended to read enough of the links suggested at the very top of this forum (when you first click on it)
that you feel a level of confidence with the process. The first three days can be demanding. Challenging. Fear is the greatest problem. Try to envision it as an obstacle. That can be dissolved, or brought to light. Also, remember, your thoughts 'ride your breath'. Check your breathing and your thinking, and you will see anxiety equates to tight, shallow, rapid breathing.
Try this.

Breathe out, and let all the breath go out, gently, and then let the body naturally breathe in. No force. Make this first breath
"one". That is: out, then in = one. (we usually do the reverse--but this way is quite calming, and has a way of reversing the thinking processes. Then do the same, up to ten. Watch the thoughts. Guide them back,if they gallop off. If you lose track, start again. No blame. By ten you should be more relaxed. Then go and study abit on EFT--
look on youtube for good, short introductions to EFT. Or google on this forum. (use the search feature)

If you have already broken the fast, (holding your breath for a reply--sorry!)then be sure and prepare yourself a little more fully, next time...That's all.Go easy. Read some of the Soil and Health links. There is nothing to fear, as they say, but fear itself. (which is just the thoughts running wild, with no gentle breathing to relax them)
EFT is one of THE best healing tools, to be used during cleansing, fasting, just plain living. Really. And it's free.
best, C