Did I kill my grapevine
It does look like that it has been pruned very severely. Usually grapevines can take severe pruning and then come back. This is a large trunk with lots of root reserves so my guess is that you will have some green growth soon. Do you have ID-126 Growing Grapes in Kentucky? There is a pruning section in this publication with some pictures so you can get a visual on how a grape vine should look after pruning.
Let me know if it leafs out and if you have other questions.