Why did you exclude your home directories from the 'du' output?
You're getting out of space with approx 7G showing remaining because you're a user, and root reserves (by default) 5% of drive space. This allows root to perform maintenance when the drive is "full". 5% of 149G is ~7.5G. (This can be changed and checked with tune2fs)
Something has used the space, and based the output you show, it's obviously in your home directory.
du -scm /home/* Will show the usage for each user's home directory, (probably just yours though).
Once in your home directory, try this to get an idea of where the space is:
shopt -s dotglob # makes * include the .dot files/dirs too du -scm * | sort -n # gathers the info, sorts so biggest at end of list That will show you what's being used in your home directory. The shopt command is important, as it makes the * (wildcard) include the hidden dot files. Without it, you wouldn't be shown the hidden files and folders. (my .kde is approx 350M, mostly because of nepomuk (which I disable file searching after it's done with initial scans) )
Midnight Commander (type mc at a prompt) is good to run around the filesystem with to see what's there. Press ALT+. to toggle hidden files on and off (there's a menu option too, but this is easier)