He confesses that he has wept and struggled to find a place of rest, but only God can give him that peace.
The word Shiggaion is used in Hab. 3:1, but is found no where else in the Bible. I don't believe it means he was drunk, but his emotional state was so severe that he was unable to behave normally.
He is impassioned about his distress and calls on God to deliver him. He cannot find any reason for enemies to assault, but he beseeches God to be just and allow the retribution if he has hurt another, but if he is unjustly accused, he seeks God's intervention.
He prays that God will cause the instruments the enemy uses to fall on his own head.
He closes with praise for God and His righteousness.
It opens and closes with the same phrase praising God's glory and majesty.