Help me :(

Here is your last loss.

You played a 3 minute game which isn't long enough for you to think properly about your moves - try 30 minute games.

You made too many pawn moves at the start - try to control the centre by starting with 1.e4 or 1.d4 then bring out your knights and bishops.

You moved the knight back and forth wasting time - try to only move each piece once until all your pieces are out.

Your king was vulnerable in the centre - try to castle to safety in every game.

You left pieces undefended and allowed your opponent to capture them for free - this is probably the most important thing. Before every move you must make sure you are not losing something.

I agree with @strangemover. I was looking at the same game. That opening you did with pawn moves to b3, d3 , f3 , and h3 is literally making holes in your defense. You lost your wandering knight when it was in one of those holes. 

Your profile says you have done 24 lessons but doesn't show which ones you have done.  I would recommend a series of video lessons by Aman Hambleton of the Chessbrahs called "Building Chess Habits"-

Just don't lose and win . It's as simple as that.

Thanks but really I can’t understand all of this

Only play your d- and e-pawns.
Play your knights before you play your bishops.
Do not move the same piece twice.
Do not pin the king's knight with your queen's bishop before your opponent has castled.

Also, try to verse people below or at your skill level, so you can build your self-esteem