That sounds like a hold was placed on your credit card and then released. Most credit cards tend to approve a small amount - in the US, if you get petrol and use a credit card, they pre-approve at least $1 USD to make sure that you can at least charge something onto the credit card.

Keep an eye on it, most holds clear up and never come back. But you should still doublecheck with your card company and confirm it was indeed a hold.

This... is looking up for you it seems. Good.