Our cat was quite old by the time we brought corie home. The cat just stood her ground and then it was not any fun for pups. I think they just have to work it out.. good luck
Our cat is six years old and apparently feels she's well established in our home. Things seem to be better the last two days, so maybe they just need time.
Hana is our 2nd corgi, but when we brought our 1st corgi home our cat had been with us for only about 4 months and he got very upset, didn't eat much and hid for about 2 weeks. It was a gradual process for them to start interacting and play with each other. It was fun watching them chase each other and play together.