hey, I think it's normal... I fluctuate about 2 to 4 lbs throughout the day. It's sorta funny though. I set my "official" weigh in on tuesdays at 5:15pm ---so I've eaten and drank all day. It just seems more "real" to me than weighing myself right away in the AM...I mean, I hardly keep that weight throughout the day.
But yea, it's normal
It's hard to know what you really weigh lol.