You always have to prepare for the obstacles that are going to come. Consequently, when they do come, it doesn't affect you mentally near as much as when you're unprepared for them.
An agent won't help you get drafted higher, won't make you win more games, and won't make you faster or stronger. They all say they can, but the people who do the drafting don't talk to agents. They talk to coaches, they watch film, they talk to the people who've worked with players. They don't talk to agents.
All winning teams are goal-oriented. Teams like these win consistently because everyone connected with them concentrates on specific objectives. They go about their business with blinders on; nothing will distract them from achieving their aims.