Why I'm get 900 elo for 5 wins?

I played and won 5 games in the row, and game gave me 900 elo... On lichess I have 1700+. Why is this like this? 

I also have one more account here with 1500 elo, but after changing sistem of calibration how I'm supposed to get mine real elo? 

It's disappointing, that I need to play years to get mine rating. I'm not spend that much time in game. So why is this sistem not working right anymore?

Even if I won every game, I need around 50 wins in the row. I play usually around 1 game per 1-2 days. To get even 1500 elo, I need to play about half of the year. What is this rules?

It's if I will gain 15 rating per game...

from the looks of it you picked the lowest level when creating your account, starting you at 400. could have picked 800, 1200 or 1600 instead.

maybe you picked new to chess that is why you started at 400 and ends with 900 after 5 games.

Do I have a choice? I thought, I'm only can choose mine lvl, when I'm playing non-authorized games.

Do it means that mine account can't be re-selected? Seems like I waisted mine time on it)

i think you have to make another account to select other options.

try to choose the advanced so that you can get higher elo. Here is the guide: New to chess: 400 · Beginner: 800 · Intermediate: 1200 · Advanced: 1600 · Expert: 2000.

Just play, your rating will settle where it should be after time. there is no shortcut.