1)
Why does it say "Yekadmuni v'Yom Edi"?
1.
Rashi: They rushed and came early to come upon me on the day of my calamity. Radak (based on Targum Yonasan, Shmuel II, 22:19) - i.e. when I wandered to and fro, and the Zifim [told Sha'ul].
2.
Malbim: When I wanted to escape the river, my enemies preceded me, to return me to the water. (Refer to 18:17:2:3.)