是在担心

is worried about

→ 是
phrase Rare #27,568
is worried about The phrase can also mean “am/are worried about,” depending on the subject. 是在 adds emphasis to the ongoing action.
CH: 你是在担心工作吗?
EN: Are you worried about work?

也许殿下是在担心塔克罗迪

Perhaps Your Highness is worried about Takrodi.

— 豹 (1963)

都是在担心一些没有的事

You're worrying about things that aren't even there.

— 利维坦 (2014)

我是在担心你会不会真的不答应让我做这份工作

I was worried that you might actually refuse to let me do this job.

— 红猪 (1992)

你是在担心我找阿和做一些乱七八糟的事情

Are you worried I’ll get Ah He to do some shady stuff?

— A Sun (2019)