trouble started here Black to play.
You chose 11...Qc7 holding the Bishop and the b7 pawn.
The Queen is actually your worse piece. She is a liability and certainly no team player.
All she can do is attack. She hates defending duties.
When you use her attacking powers to defend she sulks and when the Queen
sulks the whole army is miserable.
Basically, as a rule of thumb, never use the Queen to defend things.
The other lads don't mind doing their bit of defending but the Queen is
always the weakest link in the defensive chain. Using your most powerful piece
to defend bits and pawns should always be your last choice.
Infact it's often better to let a pawn go than hold it with a Queen.
11...Bb6 was a move. White cannot touch the b-pawn as he loses his Queen.
11...Bb6 12.Qxb7? Bc6!
And there is the 2nd rule of thumb.
Never ever take a QNP with the Queen.