תָּעָ֣ה לְבָבִ֔י פַּלָּצ֖וּת בִּֽעֲתָ֑תְנִי אֵ֚ת נֶ֣שֶׁף חִשְׁקִ֔י שָׂ֥ם לִ֖י לַחֲרָדָֽה׃
我心迷亂,戰兢使我驚恐;我所渴慕的夜晚,祂使之成為我的戰慄。
Ibn Ezra
פלצות Boasting.10A. V., Fearfulness. Comp. מפלצתה her pride (1 Kings 15:13); the meaning of the whole phrase is: The boasting of the Persians terrified me; it may also be rendered trembling; comp. יתפלצון they tremble (Job 9:6).11פלץ has, according to I. E., two meanings, (1) to boast, (2) to terrify. For the first, however, there is no authority; the instance of מפלצתה proves nothing; it means, as may be seen from the context, her idol, the object of her fear, so that all meanings of this root can be derived from the same origin, פלץ to terrify.
Rashi
the evening of my desire The night that I longed for, for rejoicing and for a banquet. In the Book of Josipon we find that he was happy since his troops had defeated the army of Persia. (Book 1, ch. 5) That night He made for me into trembling, as it is said (Dan. 5:1): “King Belshazzar made a great feast...They drank wine...(verse 4). On that very night, King Belshazzar was slain...(verse 30).” (6:1) “And Darius the Mede received the kingdom.”