I’ve never understood the sugar water thing, I prefer vitamins. But that’s up to you.
I feel terrible for you, and this is a sad lesson to learn, but I can tell you are learning from it, so stop torturing yourself over it. We have likely all done things that have been accidentally harmful without knowing. I’m guilty too, multiple times!
And honestly, I would think a 3-week old chick could handle being held by the head for a few seconds. Granted it sounds cruel, but how many of us have seen little kids pick up chicks that way?
I hope it perks up for you today.