Question

My best friend says that I am (s )to be upset about this.

Answer 1

My best friend says that I am (silly )to be upset about this.
我最好的朋友说我要是为这事而沮丧难过就真够傻的。

silly[英][ˈsili] [美][ˈsɪli]
adj.蠢的；糊涂的；不明事理的；没头脑的
n.（常用于向孩子指出其愚蠢行为）傻孩子，淘气鬼；傻子，蠢货

Answer 2

为你解答。
My best friend says that I am (sure,肯定的) to be upset about this.
我最好的朋友说，我肯定会对此感到心烦的。
解释：be sure to do，肯定会做某事。