Not at all worried about this. Yesterday I ate even a little less than usual (though mostly the same stuff...the one difference being a and I worked a little harder. The treadmill felt pretty good, and the music bumped me up to a run a few times. I also began my strength training, so I'm sore today. None of that would contribute to an actual weight gain, but any of it could contribute to an apparent gain.
I struggled with my weight for over 20 years. I tried everything to lose weight. Yes, I did 'eat less, move more' repeatedly, convinced that doing the same thing over and over would someone yield different results. Desperate, having diligently done all the 'right' things and being told by several doctors that there was nothing wrong with me except that I wasn't trying hard enough, in 2009 I tried what seemed crazy: Dr. Simeons Hcg protocol. I lost 85 lb.