I’ve been experimenting with fasting for the last few years and rarely to I make it past the second day. But sometimes it’s so much easier than others, and on those occasions, I just roll with it. If you eat because you are really hungry, for more than a few moments, that’s ok. I think listening your body is more important than meeting some arbitrary goal.
Fasting is a muscle and you do get stronger. You will have more success if you continue building your strength. Don’t worry about how long it takes you to meet your goal, so long as you are making progress.
It’s frustrating, but hurrah for still working in some fasting time! It’s hard to ‘listen to your body’ when lack of sleep, caffeine, salt, etc can all contribute to not feeling well and breaking the fast won’t help it. i hope you’re able to get some rest and be in good form for future fasts!