I picked up guinea pig food by mistake for my bunny?

Grass Hay
Grass hay is an important part of a guinea pig's diet and should always be available. ...
Stay away from "gourmet" pellets that include peanuts, seeds, colorful cereal and other additives. ...
Fresh Fruits and Vegetables.
Guinea pigs should eat about 1 cup of vegetables each day. ...
Alfalfa, radish & clover sprout.
Basil.
More items...
tricountyhumanesociety.org/pet-tips/critter-tips/139-proper-guinea-pig-diet

What to Feed Your Rabbit
Jan 10, 2013
Large, unlimited amounts of fresh hay should be offered daily. Young bunnies should be introduced to hay as soon as they can eat on their own. Mixed grass hay or Timothy hay is preferred because it is lower in calories and calcium than alfalfa. Use a good quality, high fiber alfalfa or timothy based pellet as a small part of your rabbit’s diet.
rabbit.org/what-to-feed-your-rabbit/

Sounds to me like the diets are pretty similar. I found this information at google.com by searching "guinea pig food" and "rabbit food". Google is your friend. Wikipedia.org is the second place to check for any fact based topic.