Hi Toby,
Sorry to hear about the lack of orders. Without the domain and more information, there's not a ton to go on here, but here are some things you may want to consider:
Have you checked Google Analytics to see stats like (a) if traffic to your site is down from historical levels and (b) what pages people are exiting your website from? This may help you to identify if, for instance, you just aren't attracting shoppers to the store, or if your conversion rate is the issue, and where the dropoff is happening.
Have you checked your Magento logs for errors that users may be experiencing?
Have you tested your checkout experience on mobile as well as desktop devices? and perhaps more than one browser? (ie. Chrome, Firefox, Safari)
How are your loading speeds? Is it possible that they've gotten worse? Here's a Magento speed test that could be helpful.
Is your SSL up to date? Have you checked to make sure your site doesn't have any malware and isn't on any blacklists that would cause antivirus and browser software to bar people from your site? Here's a Magento security test that could be helpful.
If your site was updated 2 months ago, and sales only dipped 3 weeks ago, it's hard to connect any dots between the site update and the lack of orders.
Best of luck!
Robert