Definitely watch your sodium intake, if you are weighing daily! A salty meal one day will throw your weight off for the next few days, and can really affect your morale; there is no need to LOOK for reasons to slip.
It sounds like you are really doing a good job so far, and having a friend to help out is a very, very good thing. Mine seem to want to encourage me to eat; it's like they fear seeing my success at this. I'm VERY glad you have someone who will help you. How was your New Year celebration? Did you maintain, or did you go nuts?