Little things add up.
- 1 tempo for 11八馬, which isn't doing much
- 1 tempo for 10七歩, which only helped me
- awkward shape on the right
- advancing your bronze instead of the silver, which would've been much better suited for the defense
... all it took was 4十銅 to ignite matters, and an opponent capable enough to recognize the opportunity.
You did win back 2.5 tempi on the defense. So at least you're in the positive there. Could've been 6 with more accurate play.
I would've retaken with the 横. Anyways, time starts from your last comment, since my premove covered that.