Besides that I play this for two moves more than I have to could someone help me spot my mistakes in this game? I feel that I messed up my opening and got a bad game from there.

 

slave defense Declined is usually followed by 4...-bf5, 5.Qb3 or 5.cxd5 followed by 6.Qb3, giving a strong attack on blacks left side.

 I think my first big mistake is 10 c5. I should have played 10 Qb3 instead. Anyone agree with that or should I have played the queen at move 5 already?