You'll be at work by now, but I hope it's all sorting itself out ok. I know how you feel, I agonise and beat myself up over the tiniest things. Like you say, at least you won't be stewing over the whole weekend. I hope it all goes well. Like everyone says, a mistake is just that. If you didn't care, that would be bad, but obviously you do (and not just in a 'oh, my god, my job' way, but in a proper caring way), and that should count for a lot.