I've got memory problems.

Hi Everyone,

I'm not new to how the mac tends to work, but i usually use programs to solve my problems. You see, when i start a new project, I immediately move all my files to my hard drive, then delete them off the computers internal storage. Then I open my project Via the file folder in my hard drive. Today, starting a new project, i opened the project to be greeted with the fact that i now had 800 MGB of internal memory, rather then the 30.9 GB i had when I started. My videos do have the Memory mass to do this effect, but after running multiple checks through 3 different memory programs, and one stress inducing manual search, i've yet to find the reason why so much of my memory just washed away completely. Some guidance or tips would be really appreciated, but steps on how to just remove bulk masses of useless Memory would be the best. Thank you so much for your time.