Hi, here i was Black, i dont really understan why i lost the game, i left the opening with a big lead.
Here some thoughts of the match: https://online-go.com/review/293858
Here the match: https://online-go.com/game/11403184
I would like a commentary about the Opening and Mid game, I lost by few point so maybe the end game cost me the match but i dont care the end game, thing that i explain in my review. Also, why i lost the game?
Thanks
P.S. Things to improve? 
So, i have to look for shape, do not create weak groups and maintain my groups connected.
Ok, Thanks 
Should i start to studied end game?
Oh… apart from the one big reading mistake, i did not think your endgame was bad. the only very big endgame you missed was the hane in the top left. you got most other points and had sente alot, which is good.
but of course you can alway try to do better, so study away 
.
The reason you fell behind in this game (after a good early game put you ahead) was that you missed a couple of opportunities to stop white from making territory in the centre.
EDIT: I added some variations in the review.
Stone 9: for fun, play R-15 sometime (ie, forces white into a more basic move).
Stone 17: not a big fan of M-3…both white groups on either side are fairly safe while M-3 does not have a lot of places to run to if needed for later…perhaps attacking the space between R-3 and R-11 would have been better, even though I agree that M-3 is trying to take away “the bigger area”…
Stone 20: this is where playing R-15 earlier on stone 9 may have helped…no with white playing stone 20, black’s corner shape seems “small”…
Stone 38: Even if it meant escaping with your life in the top right corner, some type of larger black stone extension (ie, C-8 or C-9) shold have been played prior to white’s D-8. Again, white is forcing black into a smaller shape…
Stone 85: Everything seems fairly well for black up until this move at S-8. My preference would have been to play something like O-6, to make
larger black’s center territory and also help connect to other black stones.
Stone 165: (hindsight is 20-20, but anyway)…H-8 seems like the right move, but in hindsight it probably would have been better for black to play one additional stone to save it’s bottom group…I believe this is where most of the game was lost near the end.
sorry but I don’t quite understand, it seems you are talking about a different game.