Unfortunately, if it is an upper respiratory infection (which it sounds like), some trial and error is sometimes needed to find the right antibiotic to do the trick. It took three tries to find the right antibiotic combo for my rabbit’s URI. It would be important to know what antibiotics have been tried vs. not. Some more experienced vets may offer doing a culture, where they collect a sample from the nose to then test what antibiotic would work against it — I’ve read both successes and failures from that.
Another note would be treatment time. Now, if no improvement was seen in during the 7-day med, it was probably right to discontinue it, but in general, you want a rabbit to be on an antibiotic course for at least 2 weeks, to ensure all the infection has died (sometimes you may even need longer!).
In terms of finding a rabbit-experienced vet, at the minimum, the vet should be an exotic vet, which is a formal specialization in veterinary medicine. Exotic vets will more likely than not be better suited and educated to work with rabbits. The ideal is an exotic vet who has rabbit experience. If you are in the US, the House Rabbit Society (HRS; rabbit.org) has a list of rabbit-experienced exotic vets. You can also find the web page for your local HRS chapter, and they will likely have a list of vets they personally use for their foster rabbits.
I am unsure what the clicking noise is….. but getting a mite treatment was a good measure.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.