In your case Cocoa, when you repositioned your antenna for WNED, you probably lost the line of sight for WGRZ's transmitter in South Wales.  Refer to the REMOTE CENTRAL map [Link: remotecentral.com].

Or, there may have been a tree growing or a newly built structure (apartment/second floor addition to a house) which has interfered in you line of sight.
Atmospheric and Lake conditions due effect signal reception.
You will be able to receive WIVB a lot better beginning April 13.