SQLSTATE[42S22]: Column not found: 1054 Unknown column

I believe this is because you are using backticks for your values. Change them to single quotes and you should be good

$sql = "INSERT INTO `saved_holidays` (`subscriberID`, `link`, `pubDate`, `title`, `description`) 
            VALUES ('John', '$currentFav->link', '$currentFav->pubDate', '$currentFav->title', '$currentFav->description')";

Please refer to this SO question about single quotes versus backticks if you want more information

` is for specifying fields, you must use a single quote ' for values.

$sql = "INSERT INTO `saved_holidays` (`subscriberID`, `link`, `pubDate`, `title`, `description`) 
        VALUES ('John', '$currentFav->link', '$currentFav->pubDate', '$currentFav->title', '$currentFav->description')";

 $sql = "INSERT INTO `saved_holidays` (`subscriberID`, `link`, `pubDate`, `title`, `description`) 
            VALUES ('John', '$currentFav->link', '$currentFav->pubDate', '$currentFav->title', '$currentFav->description')";

Use ` for fields only and use ' for values