stability

tell me why this happens, one day I can win 5-6 games in a row, all the other lose, a lot wrong, but opponents are not stronger than they were, but also is less, on what depends? as a stable play even at this level?

i am inconsistent playing from 1300-1700.  I have no idea how to achieve stability.

If you play someone your level, the chances to win are the same as the changes to lose. So a win/lose streak of 5 or 6 games isn't nothing unusual - there are excellent chances for it to happen quite frequently. 

Also, in playing in "blitzing" websites where your rating changes numerous times within the hour, fluctuations of 200-250 points are also quite usual - you have "off days" and "sharp days" and "days where nothing seems to work" and "days when you got that mojo!"

400 points is a bit extreme, I admit...