You were abused in your childhood, and lived your whole life with one friend you knew in the primery and after one day saving him by sacrificing yourself, you're Isekai life was even worse, with no idea what powers you wield you are discovered to be the weakest in class so your friends started bullying you with the others instead of helping you and your GF left you for someone stronger because "she doesn't wants someone that atleast is on or a level lower than her current rank". 🤷‍♂️