Dream About Forgetting Pants School

This dream is a reoccurring one. It is a nightmare but not scary like the other ones, just extremely embarrassing. I get ready for school and then go to school. And somehow I forget I don’t have any pants on ( I have underwear, just no pants) as soon as someone sees me they immediately start laughing or smiling. I honestly hate this nightmare a lot and don’t understand why I have it.( It’s not like I would ever forget something like pants or a shirt when going to school.)