firefox updated and forgot history and session data

You can try and see if there is another Profile that may have older data

You could also check the current profile to see if it has any backups, like it does for bookmarks.

So by [tabs] you do mean open tabs ? How many were there ?

I had a huge amount of tabs that would open every time I launched Firefox. I had not had time to review them and we’re going to in the future. I’m not sure if I have or had another profile. Where would I find it?

IMPORTANT: Do not close or restart the browser before you make backups of your session restore directories. See How to restore a browsing session from backup step 5. mentioning to make a copy of that data — as it would get overwritten further with subsequent restarts. Ideally look around your profile folders up in the structure, and just back up everything there again, before you can figure out which profile is which, and what you need from these.

Generally it's simple:

If Firefox starts up after an update without your history and settings, check whether your data is available in a different profile:

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it. The About Profiles page will open. This page should list at least one profile and could list many.

The profile that Firefox is currently using will show:
This is the profile in use and it cannot be deleted.

Please do not delete anything here; don't use any Remove buttons.

Do you have another profile named default or default-longnumber listed on this page? If so, you can check whether it is the one you were using recently by clicking its Launch profile in new browser button.

If it isn't what you want, simply close that new window.

If it IS what you want, click the Set as default profile button for that profile on the about:profiles page. Firefox will use it automatically at the next startup.

For more information see Recover user data missing after Firefox update or reinstall.

If neither of the above is relevant to your case and you're still in the original profile, just without restore snapshots available, you might need to look into all of the above mentioned How to restore a browsing session from backup and see if manually swapping the older sessionstore backups restores the older tabs.