The body is always in a state of flux. A lot of its processing occurs at night (which is why sleep is important). When you get up in the morning you will see a great deal of loss from the night before.
Weighing more doesn't neccessary mean fat; it could be muscle for example. It is important for you to develop muscle to help you burn calories quickier and make exercise easier. Muscle weighs more than fat so often people who lose weight feel that suddenly they are getting no results. This is not true, the muscle gain is masking the fat loss. The muscle gain will pay big dividends down the track...you just got to be patient.
If you are losing weight properly you will be taking in lots of water. Water doesn't have calories but it does have weight. Water is essential for your body to carry on its functions and is very important for weight loss.
You can simply have a full bowel. All these things will pass!
The body also undergoes other fluxations that we have little ken about. The best policy is to be aware of your body's natural cycles and ride them like the waves of the ocean. Use them...don't fight them.
I weigh my self daily; most experts recommend that you only do it once a week. If you do weigh yourself daily you must understand that one or two numbers never tell the whole story. If you can't learn to ride it out then for the peace of your mind it would be better for you to weigh in only once a week. The advantage of daily weigh ins is that it does keep you focused and on top of things.