It sounds like your rabbit has 'snuffles'. This is a bacterial infection of the airways and is reasonably common, easy to treat but often returns. You'll have to take him/her into the vet for assessment, and it's likely that an antibiotic course will be needed.
In the meantime, use a small, damp cotton wool swab to clear the discharge from the eyes and nose, and keep food and water closely available. Add some extra bedding into the cage to keep him/her warm. Most importantly, this infection is highly contagious so keep washing your hands and don't let any other rabbits share bedding or bowls without washing them first. All the best, ***** ***** me know how you get on.
While you're at the vet, I would ask them to check the front teeth, which if overgrown can extend their roots into the nose and cause similar symptoms to those you've described.
thank you very much,