YOU SAID:
My sister is so stressed out I do not know how to help her.
INTO JAPANESE
私の妹はとてもストレスがたまっているので、彼女を助ける方法がわかりません。
BACK INTO ENGLISH
My sister is so stressed that I don't know how to help her.
INTO JAPANESE
私の妹はとてもストレスを感じているので、私は彼女を助ける方法がわかりません。
BACK INTO ENGLISH
My sister is so stressed that I don't know how to help her.
That didn't even make that much sense in English.