I wouldnt worry.
Unless you are weighing your self on recently calibrated scales, they wont be exactly correct anyway, and just the fluctuation in water levels, and whether you'd been to the loo etc.
Do you weigh yourself on the same day? I always weigh less on wednesdays...seriously...I dont know why.
Ive also had scales that varied up to 3kg and that was with weighing myself 4 times in a half hour.