You're probably not losing too fast. If you were eating a high sodium diet before you've likely shed some excess water weight. Also, depleting your muscle glycogen stores from cycling will cause your body to retain less water. Taking a break and allowing glycogen stores to replenish will quickly add some of that water weight back. I have no idea what your diet is like but don't be at all suprised to see some water weight come back after a high carb meal with some rest. Three years ago I was 230lbs. I'm 5'10" and this morning the scale said 158. It took me almost three years to get to my current weight. I weighed myself obsessively every day (still do) and noticed a lot of "noise" in the numbers. Most of this was just daily fluctuations in water retention. I learned to mostly ignore the noise and look for weekly trends. I started commuting this year and that is what finally got rid of the last 10 stubborn pounds from around my waist. Had I started commuting three years ago it would have come off a lot faster.