In the opening, I think the bishop move - 5. Bd3 wasn't ideal. Then on move 6 you moved the same piece again to allow the queen to defend the d4 pawn. I wonder if you could have played 6.Nf3 instead...to develop a piece and defend the pawn in one move.
The central pawn push seemed to come to early...but these are difficult to time accurately especially in blitz.
With 8.h3 I've always been advised to avoid doing these preventative pawn moves unless there is a very good reason, might be worth looking to see if there is a stronger move here.
From the final position, after the exchange of queens it looks winning for black....but you made a good fight back earlier after the knights invaded!