Don't be upset by trifles.; Don't worry over trifles.

不要为小事烦恼。

But I do worry over it.

但是我真的非常担心。

Butt I do worry over it.

但是我真的非常担心。

Don't worry over such little things.

别为这样的小事而烦恼。

Do not worry over me, I am all right.

没有必要为这样的枝节问题发愁了。