Years ago, when they used to give ALL the shots at one time and ALL of them every year, my cats would also react like that.  Plus...I think when they're younger, it affects them more.  Now most of the shots that my cats get are only once every 3 years (including rabies), and they don't give them all the same year.   Seems to be much better for the cats.

So glad, though, that Branson is feeling better!

Ruth