Hi Peta,
In a bunny this young and just weaned, it is incredibly important that you have him seen by a veterinarian for a full assessment. If left untreated over the weekend, your bunny could rapidly decline in health and become depressed, dehydrated, and become unable to eat putting his stomach bacteria at risk for dying off.
Based on your brief description, he could be developing a condition called Pasteurella or "Snuffles" that in YOUNG bunnies can be fatal. Adults can suffer from "snuffles" for a long period of time before becoming so sick they can't function.
For more info on Pasteurella, please visit the following links:
http://www.peteducation.com/article.cfm?cls=18&cat=1803&articleid=2686
http://lbah.com/rabbits/pasteurella.htm
All bunnies should receive routine veterinary care. Young bunnies need a complete fecal exam to assess for protozoal parasites like Giardia and Coccidia and any other type of intestinal parasite that could be present.
In addition, we routinely do bloodwork screening for both Pasteurella and E. Cuniculi in all bunnies, because a large population of rabbits in the USA are subclinical carriers for both pathogens.
Please get your bunny into the vet THIS MORNING before most vet clinics close for the weekend...as it can be hard to find exotics vets that do after hours emergency work depending on where you live!
I hope you found this information helpful and supportive. Please remember to PRESS ACCEPT so that I can be compensated for my time and professional attention to your question and your pet's specific needs. I appreciate all feedback and any type of bonus!!
Best wishes to you and your pet!!
Dr. Jodi Lynn Smith
Veterinarian
Veterinarian in Small Animal Practice for 12 years