rhanson - congrats on the 12 lbs! That's wonderful to do in 2-3 weeks!
Regarding the sodium - I believe it impacts everyone slightly differently but I can tell you that for me it takes about 2 days for the full effect to show up and another 2 days for it to be gone. My Superbowl eating debacle brought a gain of about 2lbs which showed up on Tuesday. Today I am finally back to where I was on Sunday morning.
Also, check out the seasonings you're using for your meals at home. A lot of them are high in sodium and we don't realize it.
One of the best pieces of advice I've ever seen anywhere is that weightloss isn't linear. Having a calorie deficit of 1000 calories in a day won't show up as a quarter lb loss the next day. At least that's true for most of us. It's a cumulative process and sometimes you just have to monitor your own trends to find out what your body responds to the best.
Congrats on your great progress so far! Keep doing the healthy thing and the scale will eventually get with the program.