"The last time I played in an all day volleyball tournament and had not played in awhile, I was sore for 6 days and weighed almost 7 lbs more the very next day! Then when I wasn't sore anymore, the weight had gone back to normal. Well, the same is happening now."
Very interesting. Since you suffer from this soreness you may want to try a few things to reduce the "trauma". Icing the location of soreness...like the thigh for example, or when taking a shower, alternate between cold and warm. Get the water as cold as you can take it.
Also, what are you eating after the workout? Do you get to bed early enough to get a good nights sleep?