So how come my reputation total still goes up?
suggests you had around 13,000 experience points as at May 4 2013, while
indicates you had 16,251 experience points as at Jan 15 2015 -
a gain of over 3000 xp in less than two years. Congratulations!
However ... be warned that on 1st April 2018 you had 16,412 experience points, while today
you are down to just 16,357, a loss of 55.
So, if you don't lift your game, you'll be down to zero in a mere sixty two years.
Let that be a warning to you.
Update: July 4 2018: 16,298 xp. Aug 1 2018: 16,207 xp.
Update: July 12 2020: 16,166 xp.