途方に暮れる (to be at a loss)

She was at a loss as to what she should do.

I was at a loss as to what to do.

She was completely at a loss.

She was at a loss as to what to say next.

She was at a loss as to what to do.

She had no idea what to wear to the party.

She was at a loss as to which road to take.

She was completely at a loss for what to do.

She was at a complete loss for what to do.