Please bear with me as I don't know your current rig in depth, so I am just spitballing here.
I am not a software, or hardware engineer, although far back in last century, I was a Novell Intranetware CNE 4.11 (in a galaxy far far away)... So I am a bit rusty on tech issues. Also done low level printer and PC and laptop issues at banks.
Now mind: Below is a link to cleanup diskspace.
What I am presenting are scenarios which you might be doing without you knowing you are doing.
If 1 is even remotely similar with your situation, you might want to look into that.