Uh no. You are fine. In fact if you are doing 20k steps I’d suggest actually eating and not going 5 days without eating. I tried this once while also working out and it almost didn’t end well for me. Got be to be careful my dude
No. Stopping at the natural end of your fast is a win. You aren’t in a contest, the whole point is to be healthier, right? Harming yourself would be a much bigger setback than a 3 day instead of 5 day fast.
If your body needed 5 days you wouldn’t have felt so crap.
You did a 3-day fast!! That is amazing in itself. Plus, you knew to listen to your body. I’m really trying to learn more intuitive eating, so good for you for giving your body what it needed. That, my friend, is way more important. No disappointment needed!