Might have died over winter, I'm afraid. Remove all dead and dying leaves, wait and see if it recovers.

Welcome to GoY.
With this winter being the coldest in 30 odd years a lot of people have lost trees, shrubs and other plants that have survived the previous mild winters, myself included.
I lost a 5.5' Eucalyptus that I had repotted into a large tub that I couldn't overwinter in the greenhouse as I couldn't get it through the greenhouse door.
Ho hum, it looks like I'll have to make it into a walking staff instead!
Sorry for your loss.