The good times are past, return to reality and everyday turmoil. A  honeymoon, obviously, is a special and wonderful vacation with a new spouse, but when it is over begins the time for daily living and the normal drudgery of life, so this term is used whenever a  happy beginning is followed by a  hard, long slog.

“Well my first month at the new job was very nice and everyone treated me politely but now the honeymoon is over and I’m nothing special at the job.”