[Grammar] I'm at a loss what to do next

[kadioguy]

In the OALD, it says:

loss n.

I'm at a loss what to do next.
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Why does 'at a loss' is followed by 'what to do next' without something like to, to know, etc.?

For example:
I'm at a loss to know what to do next.

(update)
I find this:
https://ell.stackexchange.com/questions/5957/at-a-loss-of-for-what-to-do

By the way, user jess said, 'but how do you use is for something other than "words"′.
Is the sentence ungrammatical? (two verbs use and is)

 

[Tarheel]

There are problems. You should say:

I am at a loss as to what to do next.

Also, it should be:

Why is "at a loss" followed by "what to do next....?"

Is user jess' sentence ungrsmmatical? It sure is! Plus I can't figure out what he's trying to say.

Finished!

 

[Matthew Wai]

I guess there is a typo in his sentence—'is' should be 'it'.
'How do you use it for something other than "words"?'

 

[bubbha]

I might say "I'm at a loss about what to do next."

 

[Matthew Wai]

A similar example: I am in a quandary about what to do next.

 

[kadioguy]

No one had corrected it, so I tried.

Actually Tarheel did it.

Also, it should be:

Why is "at a loss" followed by "what to do next....?"