A.I empathize as I see this all the time and think it’s horrible, especially when it has been demonstrated that as few as one vaccine could provide a lifetime of protection. Behavioral changes are common side effects of vaccines. One of the primary mechanisms by which this manifests is the body creating antibodies to the thyroid as a result of the vaccines. I would recommend your veterinarian running full thyroid profiles or contacting Hemopet in Irvine, California for guidance. There are many calming remedies and herbals on the market for the irritability. We use Bach Rescue Remedy or homeopathic Show Aid by Professional Complementary Health Products. Herbals that contain valerian and passion flower can also be effective. Otherwise, provide a high quality diet, good supplementation and a course of antioxidants for the potential free radicals caused by the onslaught.