If you can get a heat lamp for the little one, that would be great.
I once rescued a little duckling and the person I gave him to bought another little duckling for him that was much smaller than he was. They ended up being best friends immediately.
Also, try a stuffed animal, too. But, yes, it will want to be with you or someone else all the time. It's only natural because they do the same thing in the wild if they're left alone.
Thanks for rescuing this one. There was a couple of ducklings the same age dumped at a place near where I...