Welcome to the Forum @Caitlin3 and sorry to hear you are experiencing this issue.
To investigate what could have happened I strongly suggest you to contact directly to our Support Team who will be able to take a closer look into your account (unfortunately this is something we can’t address via the Forum) and assist you further.
You can contact Support following these steps: How do I contact support
When you do, please make sure to provide them with the following information to speed the process:
- URL of all the tasks where comments have disappeared
- URL of the project where these tasks where nested
- URL of this thread so you don’t need to re-explain everything.
Hope this gets resolved soon Caitlin but if there is anything else I can do for you, don’t hesitate to ping me here and I’'ll be more than happy to help!