How can i write lack of self worth into my main character?

In my book, i want my main character to be less of an arrogant, quite unlovable character and one whos far more emotional, more vulnerable. Jared or Frazer (i haven't quite decided yet, i like the name Frazer Rook but havent quite got a surname for Jared yet, opinions please?) is thrust into a game of survival after a man made earthquake seperates the states on the coast of america from the rest of the country, and to survivors of the quake are forced into a government controlled, televised game in which they have to fend off other survivors for food, weapons etc. Frazer/Jared takes leadership of his group, but is cautious of making decisions and, after three of his group are killed in a raid which he planned, he loses confidence and a lot of self worth. How can i write this sort of vulnerable character in without making him seem weak or pathetic? thanks, liam.