Unless you have backup files somewhere . . . . . .

Always backup then you can recover to the last backup :

• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer
• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

Please let us know if this solved your issue or if need further assistance.

I need my cache back.

It's gone. Unless you have backups as were suggested by FredMcD

I just provided you with info for the future.

Also Cache is 350megs and as your browsing files and portions of websites go into the cache for faster loading if you return to pages. There is no useful information in your cache.

It takes a lot to miss the Heading in large letters and bold History which if you deleted it it is gone also.

See I deleted my Pinterest board when I was just going to delete only one pin (I don't know how it happened) and can't get it back but if I didn't delete cache I could recover it by putting my user name and board name in the search. We just started building a new house and I have so many pins in that board

https://www.easeus.com/file-recovery/recover-deleted-firefox-browsing-history.html

I would download that and check it for Virus or bad things and also after you have recovered if recover.

I used to use their Partion Program and Backup Program but some issues with other stuff. But if recover your stuff.

• https://www.malwarebytes.com/mac/

Maybe, just maybe, this will help :

https://www.reddit.com/r/Pinterest/comments/8jm2zq/how_do_i_recover_pins_deleted_by_pinterest_from/

(you'll have to scroll all the way down)

And :

https://www.easeus.com/file-recovery/view-and-restore-firefox-cache-temp-files.html