I wouldn't worry too much. Did you weigh yourself shortly after you ate? The scale will reflect that (even though it is temporary) if that's what you did. More than likely though it is from gaining muscle.
How are your clothes fitting? I notice a big difference even when I just start working out. Clothes fit so much better and I don't feel so 'blah'.
BTW-congrats on all that exercise (and the weight loss)! I know it can be frustrating when you do EVERYTHING right and the scale likes to play games. It is good for keeping track of weight but don't let it get you down; go by how your clothes feel.
Don't stress about it and you will get there eventually.