Stepping on the scale

The day after my workout wasn't too bad. However Friday was absolutely painful. My legs hurt so bad I had to hold onto the toliet paper dispenser in order to lower myself down. I had muscles in places I never knew and they ached, all of them. So yesterday I decided to step on the scale to see if any damange was made. The arrow creeped even higher. How could I know be at the heaviest I've ever been? How could I have gained two pounds since Monday?