Her decision to do so has been verified by Wealden District Council.
On her own Faceook page, Cornelie said: "it is with great sadness that I announce my resignation today to the chief executive of Wealden District Council. I was so honoured to represent the residents of Horam and Punnetts Town and I did my best to support them and help with their concerns.
"I loved working with the excellent officers and staff of the council, hard working, dedicated but always cheerful. I would I could have completed my allotted time had I not been confronted with unexpected, difficult personal problems.
"My thanks go to my ward colleague, Greg Collins who generously took on a lot of my tasks while i tried to get to grips with my new situation. He will continue to look after the ward in an exemplary fashion until my replacement has been chosen in a by-election.
"I also wish to thank my colleagues in the Alliance for their unstinting support and their patience and wish them well continuing their impressive programme to make life fairer and greener for everyone in Wealden. The new two-million community fund to be given to community groups directly is just one of the many new projects which shows this."