Thanks for reaching out to the Apple Support Communities.
I see that you imported all of your photo and video media to your PC, and then uploaded the media to iCloud. Afterwards, you then deleted the media from your iPhone storage thinking that the media was uploaded. Now, you can't find the videos that were uploaded. It's important to make sure that you have access to all of your important videos, so I'll be happy to help.
When you imported to your PC, did you import to Windows Photo Gallery using the steps in this support article:
Import photos and videos from your iPhone, iPad, or iPod touch
If so, please check your Windows Photo Gallery for these videos. Let me know if you're able to locate them.