

I know the emotional spiral you are dealing with. I am struggling to not let myself fall into that pattern of behavior any more. I believe in you. You made a simple honest mistake. You aren’t a monster and you don’t have a major moral failing. You are a perfectly reasonable human and made a perfectly reasonable human mistake.
Step one: breath. Take long slow deliberate breathes. Acknowledge you are in an emotionally elevated state and this will make thinking clearly difficult if not possible. I find focusing only on the breathing until I feel like maybe you want a nap is a clear indicator I have done enough. lol.
Step two: Acknowledge what happened objectively without assigning blame. A scheduling mistake was made. This is a detail that is important and easy to get wrong. You are neither the first or the last person to make the same error. You haven’t harmed anyone. At worst some people will be disappointed, yourself included.
Step three: What can be done? Can you adjust reservationa to attend the event? If attending the original event is not possible, can you pivot to doing other things for the reserved times? If not, what can be done to get refunds or sell (at cost) your tickets to other people?
In our current age, I think that your first sentence is almost always true.