Mine too! I lose 2-3 lbs every night - I weigh myself at night and again in the morning - it's crazy.

My normal official weigh-in is Saturday morning. My weight always goes up during the week, but down on Saturday morning. It was really getting frustrating until I looked only at the last 4 Saturdays and sure enough, there was a gradual loss every week. So I TRY not to worry too much what I weigh during the week and just focus on doing my best and recording it on Saturdays. If I don't lose one week, I keep going and usually lose more the next week.

Keep trying!