I'd try to put the nest and peep back where it was. The mother will still feed it and take care of it if she can find it.
Try egg whites. But make sure they aren't cold. Use an eye dropper. Try googling "what to feed a baby bird". Call your local vet in the morning. Odds are good they will be able to steer you in the right direction. Make sure the baby is kept warm. Baby birds can't regulate their own body temp.
Try this one. It says not to give the bird liquids, but egg white is what I was instructed to feed a baby bird that I found. There are other sites that may steer you well. Good luck.
What happened to the parents? There is stuff online, but it says they need to be fed every half hour if featherless !! Beef cat/dog food and chopped up earth worms. Are you really up to that? Try and find a wild life rescue centre if you can, best chance for survival if mum and dad don't come back.
Well done you :) Must be knackered consider yourself Godmother.
There are animal/bird rescue persons that are equipped to help. Depending on where you live -- look under animal rescue or call a local vet's emergency number or call the fire station. They can help you help them. Being a mother Robin would be rather demanding.
Heat lamp and protein by a tube would be my guess
You could... It will die otherwise. Depends if you've got the heart an energy... and if ya got a hungry kitty
google homemade baby robin food
Set oven at 350F.