OSX creates temporary files while it is running, what you are seeing is normal.
You have far too little space available on your hard drive. As a rule of thumb 10% (roughly) should be free while the Mac is running, even though you have a tiny hard drive you are far below that.
Erasing caches is a waste of your time, the Mac has to waste its time refilling them (as you are seeing)
Remove files from your drive until at least 10% (or more) is free.