Accessed my quickbooks today fter being on holiday for 3 weeks, and it has all changed the layout etc,worrying ive lost all my data, old invoices, costs,everything help?

Hello there, Becky. Let me provide information about the new changes in your QuickBooks Online (QBO). Rest assured that your data will remain safe.

QBO is taking initiatives to improve user experience by implementing changes and introducing new features across all subscriptions. Your data, including past invoices and costs, will remain intact and unaffected.

In addition, you can check out this article about the new layout and the features currently unavailable with the new experience: See what's new with estimates and invoices in QuickBooks Online.

Furthermore, you can use your creativity and personalize your invoice, sales receipt, or estimate template to match your style. You can refer to this article: Customise invoices, estimates, and sales receipts in QuickBooks Online.

Please don't hesitate to ask if you have any further questions about navigating the new layout or accessing your data. I'm always here to help you out.