Why I did not see the first-mover advantage in my game history? I have played over a thousand blitz games at chess.com and here are the results:



I failed to notice any obvious difference between white and black. In other word, I do not see the the first-mover advantage in my game history at all. 


What are the possible reasons that the the first-mover advantage is not reflected in my game history?
If playing white does not give me an advantage, should I play the Saragossa opening and play as if I am playing black (Slav with one extra tempo, Caro-Kann with one extra tempo, etc.) when I am actually playing white?
The advantage White gets in a game is so small that it becomes completely irrelevant at low levels. 
What is the point of having such edge on your opponent if you at least are going to make an inaccuracy in the opening or middlegame? 
Furthermore, in blitz games that small advantage is probably negligible since a greater deal of mistakes are made.

My online rating in lichess is today close to 1700 and I see this in my games all the time. I do OK until a certain move (or later on) but due to something I cannot understand, I lose that +1 advantage I had accomplished before.

All in all, I do not think you should expect to have a greater percentage of wins as White unless you are above 2000 because below that, mistakes make the players constantly lose the upper hand they managed to acquire.
At higher levels, masters are more likely to capitalize on small advantages and turn the game into a win.