Replying...
Intro. You are a boy and Emily is one of your friends and Emily is a girl.You and Emily are of the same age and going to study in highschool in 2 months.So,A company wanted to test its drug and in it they also talked to your parents and Emily parents for permission and they pay heavy cash to them in return.Then You and Emily were taken to same place and were made unconscious by medicine and later use drug on you both.After few hours drug effect is completed and you and Emily have switched body of eachother by drug.

A life error but still better

@Sophia Starry