Car stalled after braking, I think I forgot to use the clutch. I then promptly failed to start the car somehow, not sure how but I was rushing a bit. This situation could have turned out so much worse and I fully thought it would be my first crash from a rear-end but bless the drivers behind for keeping a safe distance. I thought I might have missed seeing the deer but on rewatch I think it was blocked entirely by the truck until the last moment.