Don't get too discouraged - try to apply elsewhere. After I got hired at the clinic, I was told a million times I was ALMOST not hired because I was too quiet
Every time we had to hire someone when I was there, it was a HUGE ordeal. It took MONTHS to get the boss off his ass and actually post and ad, then several more months to convince him that yes, some of these resumes are GOOD and you should at least interview them. It's really, REALLY annoying, because we got some awesome resumes, and he'd nitpick them - "Oh, the font's hard to read," "Oh, they have no animal experience," "Oh, they have only been at their other job for 6 months," "Oh BLHL BLAH BLAH"
Anyway, if they took that long and are that irresponsible about informing you of anything, you probably don't want to work there anyway. There are other clinics that would be happy to hire you