Missing Numbers tabs from April 2024 to present on my iMac running macOS 15.4.1

I have a numbers file which I use to manage my businesses income and expenses. From the start of 2024 I make a new tab for every month. So I had 12 tabs for the months of 2024 and 4 tabs (until now) for 2025. Today I opened the file and every tab from April 2024 till now is non existent. I tried reverting to previous versions of the file but it's all the same. It updated a few days ago and I feel that might be it. I am on macOS 15.4.1. I checked on iCloud.com and it's the same. Its like this:

When it should be like this:

[Re-Titled by Moderator]