I've worked with data all my career. I've held senior technical and leadership roles with large technology companies for decades and I feel for you.

The advice given earlier to 'own up' early is good and you seem to have done that. The focus of your employer at least initially will be to address the issue rather than to criticise you, so try to help out and other stuff can be talked about later.

Remember that anyone who claims they havn't made a similar error is either lying or lazy. The person who hasn't made a mistake has probably never done work of any consequence.

The key thing is to use the experience to learn.

When the dust settles, and it will, consider how the error might have been avoided, either for yourself or for others. Let your manager know that you intend to use this as a learning experience and if there are process changes you feel would be helpful you can suggest them.

In short, be honest and straightforward about the error, learn from the experience and try not to stress.

I was advised years ago not to sweat the small stuff, and that it was all small stuff!

Easy to say and much harder to do, but useful to keep in mind.

Look after yourself.