I’m extremely worried

and losing hours of sleep over this, what could i do
At present, it probably needs the same things as any other duckling in the first few hours: to stay the correct temperature, finish drying off, take a lot of naps, and flop around practicing how to use its muscles.
Since it just absorbed the yolk, there is no need to worry about feeding and watering just yet. I would not provide a water dish at present, because it's more likely to drown than to drink.
You might just make sure it's safe and has the correct temperature, and do other things for a few hours (take a nap, or go to work, or do the dishes & laundry, or whatever else your day calls for.)
It’s paddling around, legs don’t seem to work. the belly also has an open wound and it is not moving well. it’s a little fighter, but it has cataracts and doesn’t react to any light at all. i’m 90% sure it’s blind, but i’ve never brought up a blind duckling before and i have brought up and imprinted one, at that.
Some of that may be normal for a just-hatched duckling, rather than indicating a problem.
But if it does have as many problems as you think, there may be internal problems as well. Raising it might be difficult, or might even be impossible.
It's still too early to really be sure. So start with the obvious (safe place, correct temperature), and re-asses regularly to see how it's doing.