If you have a Time Machine backup of your internal boot drive made before you deleted those photos you can restore the library from just before the deletion and recovery those photos and videos. Be sure you select save both versions and that you have enough room on your boot drive to hold both your current library and the restored library.
Export those photos/videos that you deleted from the restored library and import into your working library. Then you can delete the restored library to clear up disk space.
If you don't have enough room to hold both libraries try deleting any local snapshots created by Time Machine with Disk Utility:

Also delete any installer files in the Downloads folder that you've already installed.
