Re: Tell me the truth, am I hacked?
I would focus on network traffic in your instance. If something is eating up bandwidth then start with and see what processes are using lots of cpus. You could try to run on the suspect computer, but it's best to watch network traffic from another machine using tcpdump or Wireshark.
When you have a process name from top then Google it to determine if it's legit. Then you can determine if it's a hacker or if it's some process that has gone wrong.
"If somebody thinks they're a hedgehog, presumably you just give 'em a mirror and a few pictures of hedgehogs and tell them to sort it out for themselves."