I would like to ask you some questions to better understand your issue.

How long have you installed Firefox? Does your history show the last 2 days history each day (in other words the last 2 days are "shifted"), or did the problem start today and you lost your history until the other day?

In case you use "Clear history when Firefox closes" or otherwise clear history.

• do not clear the Browsing History

• Tools > Options > Privacy > Firefox will: "Use custom settings for history": [X] "Clear history when Firefox closes" > Settings
• https://support.mozilla.org/kb/remove-recent-browsing-search-and-download-history

• Clearing "Site Preferences" clears all exceptions for cookies, images, pop-up windows, software installation, passwords, and other website specific data.
• Clearing Cookies will remove all specified (selected) cookies including cookies with an allow exception that you want to keep.

If you use cleanup software like CCleaner then check the settings for the Firefox application.