SKAction problems when reloading the game - swift

Question

I'm having some problems with a SKAction when clicking retry after the player dies. It's the shooting SKAction that I'm having difficulty with. It's shooting well when I run the game but when I click "Retry" to play again only one bullet fires. After that, the SKAction stops. All the other SKActions work when i play again, but not that one.
I know what the problem is. I have all the relevant functions in a func called initialize() that I add in the didMove. But I'm having difficulty calling some of the functions there since the functions have a parameter.
These are the shooting functions I have:
func fireMissile() {
let missile = SKSpriteNode(color: .yellow, size: CGSize(width: 20,
height: 5))
missile.name = "Missile"
missile.position = CGPoint(x: player.position.x + 28, y:
player.position.y + 10)
missile.zPosition = 2
missile.physicsBody = SKPhysicsBody(rectangleOf: missile.size)
missile.physicsBody?.isDynamic = false
missile.physicsBody?.categoryBitMask = ColliderType.Bullet
missile.physicsBody?.collisionBitMask = ColliderType.Enemy |
ColliderType.Boat
missile.physicsBody?.contactTestBitMask = ColliderType.Enemy |
ColliderType.Boat
let missileFlightTime = travelTime(to: missileDestination, from:
player.position, atSpeed: missileSpeed)
missile.zRotation = direction(to: missileDestination, from:
missile.position)
self.addChild(missile)
let missileMove = SKAction.move(to: missileDestination,
duration:
TimeInterval(missileFlightTime))
let missileRemove = SKAction.removeFromParent()
missile.run(SKAction.sequence([missileMove, missileRemove]))
}
func travelTime(to target : CGPoint, from : CGPoint, atSpeed speed :
CGFloat) -> TimeInterval {
let distance = sqrt(pow(abs(target.x - from.x),2) +
pow(abs(target.y - from.y),2))
return TimeInterval(distance/speed)
}
func direction(to target : CGPoint, from: CGPoint) -> CGFloat {
let x = target.x - from.x
let y = target.y - from.y
var angle = atan(y / x)
if x < 0 {
angle = angle + CGFloat.pi
}
return angle
}
And then we have the didMove function:
func initialize() {
score = 0
physicsWorld.contactDelegate = self
createPlayer()
createBG()
createWall()
spawnEnemiesLeft()
spawnEnemiesRight()
spawnBoat()
fireMissile()
createlabel()
}
When i try adding the "func travelTime()" and func "direction()", it requires for me to also add the CGPoint for the "to target" and "from", and I don't know what to type in there, I don't know if thats even the way to go, but it should be.