Oel vs. supergo: Lost my center group

Player name: 
Oel
Player rank: 
2k
Player color: 
White
Opponent name: 
supergo
Opponent rank: 
2k
Review status: 
reviewed
Reviewer: 
spiritburd
Review rating: 
Review instructions: 

Dear reviewer,

Thanks for taking the time to look into my game. I lost my big center group in this game and clearly lost it. So generally I would like to know where things started to go wrong. Think besides technical issues I made some big strategical mistakes.

I also left some specific qustions.

Thanks!
Leo

Game summary: 

here you go :)

Commented sgf file : 
Sorry, your browser doesn't support WGo.js. Download SGF.
File grumpyme.sgf Fullscreen
Sgf file: 
File 2015-04-19_Oel-supergo.sgf Fullscreen
Request uploaded by: 
Oel