Take a breath and act in this order:
1. Dial 159 right now from any UK landline or mobile. This connects you straight to your bank's fraud team — they can freeze the card and watch for any in-flight transactions.
2. Change your online-banking password on a different device (use your phone if you entered on the laptop, or vice versa).
3. Enable 2FA on your bank app if it wasn't already on.
4. Report to Action Fraud at actionfraud.police.uk — get a reference number, it helps with any refund claim.
5. Check your credit file at Experian, Equifax and TransUnion over the next 30 days — scammers often try to take out credit immediately.
The fact you've realised within the same day is excellent — recovery rates for APP/card fraud are highest in the first hour. You will probably be fine.