What if my mistakes directly lead to someone else getting hurt?
Cfr I clipped a motorcycle with my car a few years ago. Guy broke his leg and totaled the bike and my car. You better believe I'll feel guilty for that one until the day I die.
I guess my mistake was simply not being attentive enough to the road. I wasn't speeding, I wasn't under the influence (it happened as I was trying to pull in to my work's driveway), I wasn't sleepy or tired. I simply somehow did not see the motorcycle coming towards me.
There was no malice involved, nor negligence, but it's still my responsibility to pay attention to all hazards on the road and act accordingly.
Sometimes our brains don't work properly. It's ok. You've held yourself accountable. You're a bit more careful now, and so is he. That's enough - it has to be.