The Summoned Hero in a Multiverse

Twelve is still an age when girls love to dream. My fate changed on my birthday... In my sleep, I was summoned to a world of swords and magic. Then the person who summoned me said... "Sorry, I summoned the wrong person. Can I return you?" (╯‵□′)╯︵┻━┻ Why is that the first thing everyone I meet says whenever I'm summoned?? ╮(╯_╰)╭ Still, after a while, I got used to it... Because time flows differently there, I was summoned more than 300 times over three years, staying in each summoned world for anywhere from 10 to 50 years. Time for me was measured according to the world I belonged to. But when I was 16, something went terribly wrong after I was summoned... I couldn't go back...%>_