My girl had a similar reaction. It was to the lepto though which makes things easier for us. She doesn't get DHPP anymore just because she doesn't need it. We do rabies still. If your vet isn't comfortable doing anymore, at least they care enough to stop. It's just going to be miserable trying to keep your doggie safe from all of these diseases for life.
Hoping for high titers. There would be a lot less worries.