RStudio crashing on Ubuntu

My RStudio has suddenly started to crash when opening a file (R or Rmd).

I get this weird pop-up and I have to force kill it. This error also pretty much freezes all other open applications like browsers.

RStudio opens up fine. I can run code in the console and that works. I can create a new file and run code from there. But, if I try to save that file, then it gives this error. So far it's only when I save or open R/Rmd files. R through the terminal works perfectly fine too.

This started yesterday when I filled up my disk and ran out of space. Then I couldn't save anymore obviously. Since then I have cleared space on my drive. There is 35GB of free space on my drive. And the system has been rebooted.

I have tried to remove the .rstudio-desktop directory from my home. That didn't help. Then I uninstalled and reinstalled RStudio. That didn't help either. Anyone has any ideas?

R version 3.5.2 (2018-12-20)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 18.04.2 LTS

RStudio Version 1.1.463 – © 2009-2018 RStudio, Inc.
Mozilla/5.0 (X11; Linux x86_64) 
AppleWebKit/538.1 (KHTML, like Gecko)
RStudio Safari/538.1 Qt/5.4.0

EDIT: Error logs added as suggested.

Ran journalctl -f and got as below:

Mar 15 14:41:05 elmo systemd[1]: Starting Process error reports when automatic reporting is enabled...
Mar 15 14:41:05 elmo whoopsie-upload-all[14945]: ERROR: whoopsie is not running
Mar 15 14:41:05 elmo systemd[1]: apport-autoreport.service: Main process exited, code=exited, status=1/FAILURE
Mar 15 14:41:05 elmo systemd[1]: apport-autoreport.service: Failed with result 'exit-code'.
Mar 15 14:41:05 elmo systemd[1]: Failed to start Process error reports when automatic reporting is enabled.

Ran rstudio from the command line and got below:

load glyph failed err=6 face=0x2372ac0, glyph=2798
load glyph failed err=6 face=0x2372ac0, glyph=2798
[1]    14976 killed     rstudio

Rstudio crashed and was killed in both cases above.