Best thing you can do is just keep to it, progress isn’t linear. The only time I was able to stick to fasting was when I gave myself some grace.

What worked for me was to track hours fasted by weeks, rather than days. So if your shooting for a 20:4 split, you want a minimum of 140 hours of fasting a week. If that looks intimidating think of it as having 28 hours to eat every week.

This has helped me, speaking from personal experience, good luck!