Missed an exam this morning …

I somehow misremembered the starting time of an exam worth 50% of my module. I only realised my mistake 5 minutes before the exam finished and managed to download the paper and submitted my rushed attempt 45 minutes late.

I feel so stupid and useless and wanted to know if anyone else has done the same? I think I qualify for a resit but if not it’s a large amount of marks to loose. I’m currently achieving 72% so could be the difference in a grade.