GIMP :: Drawing Tools Stopped Working All Of A Sudden (2013)

I'm using GIMP in my own language so the tools names translation might not be 100% accurate.

Been using GIMP (2.8 and just switched to the latest one) for a while now, it's been nearly a year on this PC (Windows 7 64 bit, relatively recent hardware, 8 Gb of RAM, etc.) and it's worked smoothly up until a couple of days ago when it stopped working as intended all of a sudden for some reason.

Whether I use my Wacom tablet or the mouse none of the tools that normally allow you to draw (pencil, brush, airbrush, etc.) work anymore (cropping, distorting the image and the likes work fine though), doesn't matter if it's a brand new document or an old file.

The funny thing is that when I go to the "Edit" menu it'll allow me to rollback and undo whatever I did with the aforementioned tools, even though there's no trace of it on the empty canvas itself.

I tried to uninstall and install the software back but it didn't do the trick.This is really irking me as I'm working on an illustration that is due in a week and I basically had to stop working on it altogether because I haven't been able to get rid of this problem (also I can't seem to find anything about this specific issue on the net).