Awwww, don't be too hard on yourself . That chick looks like it shouldn't be weaned for another week or more. Without hourly feeding (wild birds are fed much more frequently than parrot species), the chick would have passed on anyways. If you find more uninjured, generally healthy, but not weaned birds, you can go to your local PetSmart and buy Lafeber's Handrearing formula or Kaytee's handrearing formula or Pretty Bird. Generally, I would use Lafebers as I think Kaytee's is more formulated for the large parrot species like Amazons, Cockatoos, and Macaws. This is all just for through-the-night feedings. Also, keep a heat lamp (regular lamps don't project much heat) and place a towel over half the cage. It's generally a good idea to use a plastic fish tank or plastic tub. It's also recommended to place a heating pad underneath the tub/cage/tank. As soon as the vet opens his doors, demand to be taken in and demand they teach you to feed properly or find a wildlife rehab center for the chick. Rest in Peace, little one.