Life In 19x19

I thought I lost the game since White got large amounts of territory and I played a few wasteful moves. And that is with me receiving 2 stones! Judging from my passive play, I was not in a fighting mood today In the end I won by 1.5 pts. Much obliged in advance for your kind commentary.

I just have a few minutes, but here are some comments:

Blocking at Q3 is more efficient, and secures points in the corner.
Same comment. I suspect in the game moves, you're trying to prevent white from getting a lot of points in the lower center-ish area, but the corners are bigger here.
This move doesn't do much except force white to get stronger. Instead of B28, think about jumping in at C17 or playing R17. Locally, if you want to secure territory, the move is C11, but it seems pretty small right now.
careful here. This shape has a lot of potential weaknesses. As white, I would have tried F7, if black G8, then white E6, black E5, white C5. Black can respond to F7 with E7 instead, and white wouldn't gain too much, but there are still issues.
The problem is still there.

The weaknesses in black's shape are exploited later, though black could have handled it better starting around white 139.

Some thoughts:

10: Take the corner with Q3
16: Same again.
26: I would let white keep pushing. Your shape is weak here and it does get exploited later.
58: This isn't necessary because of the Q6 stone.
120: The D10 stone means you can play A9 here.
142: This isn't where your weak. White can get some forcing moves but he can't really expect to hurt those stones, so focus on protecting one of your more severe weaknesses. I would probably play H10

Also note that if white plays the atari at F7 you can't connect at G8 because then he can capture F6 with E6, (Connecting at E5 would only make things worse), but you can pull back at E7 and the damage is minimal.

52 at t13 seems possible