No reason to be worried about it really. Fluctuations in weight are as normal for athletes as the changing of the seasons. It's only when it comes down to the big meets that it makes a difference. Like you said.
Was this sprint specifically for novices?
Ye, you're right, I'm just not used to having excess pounds anymore.
We had two sprints, one short and mostly beginner-friendly, the other long and intermediate level. This was the first time I had to instruct people on how to orienteer on a sprint map, and it seems such park-O style maps and courses are much easier for people to grasp quickly.