Confusion

I have a conundrum, maybe someone will be able to give me an answer:

In the morning, if I weigh myself before and after a workout, I am typically a pound or so lighter post-exercise. I attribute this to water loss from sweating, but who knows really, maybe you actually do lose weight that quickly. Yesterday though, after volleyball I weighed in at 167.0, so I was very excited that after yoga I might actually be like 166.5 or something. In fact, I weighed 168.2, and I didn't drink water during yoga, nor did I sweat. Can anyone explain why this might happen?

In any case, it's not like that bothers me because I know I am making progress and one or two pounds' difference is really not difficult to handle, I am just curious really.

Anyway, last night I ate very late because of my many physical activities, so naturally I didn't sleep well at all. I woke up about every hour or two thinking it was time to get up (at 11:15, 2:30, 5 am for example). Finalement, I got up at 6:10 for a light workout. I did 30 minutes of mostly walking, with a few jogs here and there. I did one set of push ups, the plank, one set of crunches and then decided to throw in the towel. I don't want to push too hard after yesterday's workouts.

Now I am eating a bowl of cereal, getting ready to work from home and cleaning my apartment a bit since building inspectors are coming in and out of people's apartments today. I will probably take a walk at lunch to get some sunshine and fresh air since the forecast for this week is depressing. Then tonight it's 5@7 time!!!

Alright, I am off to get set up to work, have a great day everyone!