In addition to Raths excellent answer I just want to add an observation from experience.

You don't have to justify anything, you did nothing wrong, yet you still missed an opportunity.

You need to put it behind you but look at what happened as you chalk it up to experience.

Opportunities can switch on and switch off in the blink of an eye in many facets of life. If you really want something, you catch the next train, don't show up to driver training, jog home, whatever it takes.

You can't relive the moment, but you can learn from it.