`Hi @joannaritsoni!
It is not usual that you lose information or settings when activating/deactivating your theme and plugins; however, we recommend you make sure you have a backup in place of your site and database before making any changes.
Another thing you can try is to clone your site to a staging environment, and monitor/perform tests without modifying your live site or impacting customers. Many hosts provide staging facilities; it’s worth checking in with them. It’s also possible to do it using the free WP Staging plugin. Link: https://www.ads-software.com/plugins/wp-staging/.
You can find more information here: https://woocommerce.com/document/how-to-test-for-conflicts/#section-2
Let us know how it goes for you!