Am Montag, 19. März 2018 schrieb William Morder:
[...] About a month ago, I had something like 2.2 gb free in my / (sda1) partition; then it went down to 1.5, then to 1 gb, then to 800 mb, 600, 400, 200, and now I am at about 165 mb, and sometimes it goes down to 0. In all this time, I haven't installed anything new, or done anything different.
I would suggest you make a clean installation.
nik