Don't freak out about the scale. Your weight changes constantly throughout the day depending on how much water you have, how much salt you have, what your hormones are like that day, the alignment of the stars....okay, maybe not that last one :) but seriously, your weight is never constant, so don't worry about what the scale says.
You said that you didn't buy anything sweet. Great job! There's a victory! Figure out some other little goals that don't depend so much on poundage. That or measure yourself. Measuring always encourages me because I do a lot of weight lifting, and since I'm female that means that I actually stay the same weight or even gain it, but I get smaller all over the place, it's amazing. I literally measure my body EVERYWHERE just because I'm so curious to see where is it going to disappear from this month.
Anyway, don't freak out about the scale, it's not a very accurate measurment anyway, find a different goal and celebrate when you achieve it.
You can do it!