Questions I have about filibustering while watching the filibuster (June 15 & 16)

I'm watching some of the filibuster, and I have questions about the process that perhaps someone(s) can help answer
  1. Why do the senators refer to Sen. Chris Murphy as "my colleague from Connecticut" or "the senator from Connecticut"?
    Is this a rule? Is this just fancy congress language?
  2. It is 12:11 a.m., how long does Sen. Chris Murphy have to filibuster?
    It's been going on for 11+ hours
  3. According to tweets, it seems like republicans aren't really present right now. If the filibuster ended would they come back to pass the bill that the democratic senators are trying to stop?
  4. Part two to the above question: how are you allowed to just leave work if stuff is still going on?
    Last summer at my internship, I would stay late sometimes because things were still going on at the office. I wasn't paid for that. These senators are being paid to represent their state, but they just get to peace out because they disagree?
  5. When the other senators ask these questions, is Sen. Murphy allowed to go to the bathroom or eat a granola bar?