Who is that girl?

Who is this person who just a few short hours ago was smiling and cracking jokes with the residents and kiddies? Who was industriously handing out keys, and change and sorting out accounts? Who was reorganising the office and photocopying and returning enquiry calls? Who was calmly discussing the weather? Who is that girl and how is it possible that she can go from that, to me, right now... fighting off tears, feeling hopeless and totally without energy or motivation? How is it that I can switch so rapidly between the two, and why can I not sustain that calm and positive persona?  The ashtray is overflowing, my bedroom is a wreck, I've only eaten two chocolate truffels and a handful of dry crackers in the last 24 hours. I can't seem to do anything but lie here and vegetate. I don't know how I'm going to make it through christmas, I don't know how I am going to make it through full stop. I keep thinking 'if I don't get some sleep soon, I am going to..." but I can't figure out how that sentence ends. I can't go on the way I am going, but I don't know what the other options are really? "Lose my mind", "Take to my bed and just not get up" "Take the final train"... I just don't know... I just don't know.