Water Retention when I resume?

I've been injured and not able to work out the last several days. Have been doing daily workouts (mostly cardio/some strength) for months and the few days off has resulted in a rapid loss of weight --- about 5-7 lbs of water apparently being held in muscle? Not sure.

QUESTION is ... when I resume my workouts, will I probably re/gain water ... ? Any way to mitigate that?