Fitbit Question

I use my fitbit all day long. Usually I get to about 12000 steps. Today, I wore it and took it off to go swimming with my son. I counted the swimming as Water Aerobics and earned about 500 calories for it. Now it says I have a negative adjustment on my fitbit adjustments. What does this mean? If I make it to 12000, do i not get credit for both?

Help!!!