surveillance software at work

I work for a mid-size consulting company and now I'm facing dismissal
because my boss's caught me several times doing private correspondence,
chatting and downloading software from the Internet during work time.

They use statlook surveillance software which tracks your activities
while doing computer work. They monitor visited websites, total time
spent working and pausing, keystroke/click count and so forth. The
problem is, they didn't put my on a notice, they introduced the
surveillance system. I didn't know being watched. I didn't even know
they can grab the current screenshot and even follow it "live" just
like on Big Bruv.

I don't want to get a sack! What shall I do now?

JC