I had posted this message yesterday but it did not show up. Anyway...

I have a female 4-month old Golden named Amber. She has just completed
her course of 4 injections spread over 2 months. She has suddenly
developed very weak hind legs. She struggles to stand up and when she
moves it's in a peculiar fashion with the legs appearing bent. She is
otherwise perfectly normal : mischievious puppy behaviour, healthy
appetite, normal bodily functions. She's had this problem for about
two weeks now. Can someone help please?