OTB Game - Weak game

I'm black, I know I played some weak moves... but i'm putting myself out in the open for scrutiny and to help my thinking. I've done my best to memorize the game... it feels correct though.

You played well.  I don't think it was a Najdorf, it was a closed Sicilian. The Najdorf is one of the lines of the open Sicilian, when white plays 2 Nf3 and 3 d4. (Yes, it could still have translated to a Najdorf after 4 d4 but 4 Bd3 showed your opponent was not interested in the open Sicilian.)

I think that the a6 and b5 lines to post your bishop on b7 and your excellent d5 break are typical of the closed Sicilian.

I wonder what you think of 13..d4 as a way of keeping white's black bishop out the game a whilte longer.  As it turned out, I think white got back to equal.

I wasn't wild about 18.. Ra7. I think your rooks belonged on the open b and c files.

I think you had a good advantage at the end and had excellent winning chances, even if white hadn't blundered his bishop.

Thanks notmtwain
I think my frustration was the game was starting to feel equal when I was sure the opponent made more innaccuracies than I.

In the game I didn't think hard enough on the 13. ...d4 idea. I was too locked into the them of breaking through on the queenside that it looked like i'd have stunted the attack. Now you suggested it, I should remind to tell myself if the situation will change, so must my priorities - e.g. use the development advantage and switch over to make some central or kingside pressure.

18. ... Ra7 seemed like the fastest way to doubled rooks, without committing to which file I want to apply pressure on. I'll thrust this game through a computer later today.