Indeed. Prior to the events shown in "The Cage", he had a number of his crew killed on a mission that went completely sideways (from MA):
The dude was definitely having a very bad day.Four years after assuming command of the Enterprise, Pike led a landing party to Rigel VII. On this mission, the group was attacked by the Kalar, and Pike himself was trapped by one of the warriors in an abandoned fortress. Three crewmen, including Pike's own yeoman, were killed, while an additional seven, including Spock, were injured, some severely. The loss weighed heavily on Pike; with all the strain and overwork that followed, he began to question his own continuance as starship commander. The Enterprise then set out for Vega colony to hospitalize the sick and injured. (TOS: "The Cage")