A family of Microsoft relational database management systems designed for ease of use.
Hope you have a backup of the database, or at least of the data that went into it.. :-{(
A Query is just a VIEW of the data in your table. When you copy and paste data in a Query, it is actually updating - overwriting and permanently destroying - the data in the table.
Query datasheets are not particularly good for data presentation (this experience is just one reason, they are MUCH too vulnerable to data-destroying mistakes!). You should instead create a Report or a Form based on the query, and do your layout work there instead of in the query.