Sharing my own experience.. I have tried waterfasting a few times each aiming for 5 days and found that they were different in terms of energy and cravings. I’m 40F and my weight is ok in my opinion: 58k for 164 cms and i do it to lose a couple of kilos usually and to detox or when i feel I’ve been having too much sugar. Usually first two days are smooth sailing, but the third differs. Sometimes i find it takes a long time to beat the sluggish feeling on waking up. After drinking water, mixed with salt and acv and moving around it gets better. Fourth and fifth days are usually a struggle. I get tired a lot and need to rest. So i try to stay away from anything that needs mental or physical effort. The way i see the while fasting concept these days is that I should integrate it in my lifestyle but I also realize that for important tasks that require energy i would break the fast. I would rather plan the fasting around the important appointments. If I were you, and especially since you don’t know what to expect, I would break the fast just to be the best I can be for my thing. Good luck whatever you decide!