I am feeble - The word used here means properly to be cold, or without warmth; and then, to be torpid or languid. Compare Genesis 45:26. Would not this be well represented by the idea of a "chill?"
And sore broken - This word means to break in pieces; to beat small; to crush; and then it may be used to denote being broken in spirit, or crushed by pain and sorrow: Isaiah 57:15; Isaiah 53:5; Isaiah 19:10.
I have roared - I have cried out on account of my suffering. See the notes at Psalm 22:1.
By reason of the disquietness of my heart - The word here rendered "disquietness" means properly "a roaring," as of the sea: Isaiah 5:30; and then, a groaning, or roaring, as of the afflicted. Here the "heart" is represented as "roaring" or "crying out." The lips only gave utterance to the deeper groanings of the heart.

I am feeble and sore broken - I am so exhausted with my disease that I feel as if on the brink of the grave, and unfit to appear before God; therefore "have I roared for the disquietness of my heart."
That David describes a natural disease here cannot reasonably be doubted; but what that disease was, who shall attempt to say? However, this is evident, that whatever it was, he most deeply deplored the cause of it; and as he worthily lamented it, so he found mercy at the hand of God. It would be easy to show a disease of which what he here enumerates are the very general symptoms; but I forbear, because in this I might attribute to one what, perhaps, in Judea would be more especially descriptive of another.

I am feeble and sore broken: I (g) have roared by reason of the disquietness of my heart.
(g) This example warns us never to despair, no matter how great the torment: but always to cry to God with sure trust for deliverance.

I am feeble,.... Both in body, natural strength being weakened by the affliction, and dried up like a potsherd by the heat of the distemper; and in soul, being weak in the exercise of faith and other graces. The word is used of Jacob, fainting at and disbelieving the news of his son Joseph being alive, Genesis 45:26;
and sore broken; in his constitution with the disease, and in his mind with trouble; especially for his sin, and under a sense of the divine displeasure; his bones were broken by his fall, and his heart broken with a sense of sin, Psalm 51:8;
I have roared by reason of the disquietness of my heart: which was like the raging of the sea, as the word (l) rendered disquietness here signifies; and to which the uneasiness and restlessness of wicked men is sometimes compared, Isaiah 5:30; and so great was the disquietude of this good man under affliction, and sense of sin and wrath, that he had no rest night nor day; and could not forbear crying out, in a very hideous manner, like the roaring of a lion.
(l) "prae fremitu", Tigurine version, Vatablus, Junius & Tremellius, Gejerus, so Piscator, Cocceius, Michaelis.