I accidentally deleted my photos and videos, how do I get them back?

I take it, you have checked already the Recently Deleted album in Photos? "Recently Deleted" is the only safety line offered by Photos to recover accidentally deleted photos. If the photos are still in Recently Deleted, you can select them and put them back (If you're missing photos or videos in the Photos app - Apple Support). If the photos are no longer in Recently Deleted, they have been permanently deleted. If you have been using iCloud Photos they will also be deleted from iCloud and you have to fall back on your own backups.

Do you make regular backups on your computer?