Because you're not training as hard, you're burning fewer calories. So cutting down on food is not doing much. You need to work out with weights and do some aerobic activity in the off-season. Don't switch completely to another sport, because you risk losing your ability as a sprinter. Talk to a sprinting coach about exercises you can do to keep an edge and not get injured.
Basketball is great because it's explosive, too.
The fear is you really want to do good, you want to win, and you never know about the uncertainty of athletic contests. The fear is of the unexpected. It's like kicking a football that may bounce weird. This is sports and it's still a game. I study for my fights.