Updated working i think ?

int pirsensor = 0;
unsigned long startMillis;
unsigned long currentMillis;
const unsigned long period = 3000;  //3 sek
const unsigned long hold = 6000;  //6 sek
int check = 1;
void setup()
{
  Serial.begin(9600);
  startMillis = millis();  //Startar tíd?
  pinMode(13, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(2,  INPUT);
  digitalWrite(13, HIGH);
  digitalWrite(12, LOW);
  digitalWrite(11, LOW);
  
}

void loop()
{
  
  if (digitalRead(2) == HIGH && check == 1)
  {
    currentMillis = millis();  //Hvussi leingi hevur programmi koyrt
    digitalWrite(12, HIGH);
    digitalWrite(11, LOW);
    check = 2;
  }
  if (currentMillis + period < millis() && check == 2)
  {
    currentMillis = millis();  //Hvussi leingi hevur programmi koyrt
    digitalWrite(12, LOW);
    digitalWrite(11, LOW);
    startMillis = millis();
    check = 3;
  }
  if (digitalRead(2) == LOW && currentMillis + period < millis() && check == 3)
  
  {
    check = 1;
    currentMillis = millis();  //Hvussi leingi hevur programmi koyrt
    digitalWrite(12, LOW);
    digitalWrite(11, HIGH);
    startMillis = millis();
    check = 4;
  }
if (currentMillis + period < millis() && check == 4 )
  {
    currentMillis = millis();  //Hvussi leingi hevur programmi koyrt
    digitalWrite(12, LOW);
    digitalWrite(11, LOW);
    startMillis = millis();
    check = 1;
  }
  if (digitalRead(2) == HIGH && check == 5)
  {
    currentMillis = millis();  //Hvussi leingi hevur programmi koyrt
    digitalWrite(12, HIGH);
    digitalWrite(11, LOW);
    check = 6;
    currentMillis = millis();
  }
  if (millis() - currentMillis + period > millis() && check == 6)
  {
    currentMillis = millis();  //Hvussi leingi hevur programmi koyrt
    digitalWrite(12, LOW);
    digitalWrite(11, LOW);
    startMillis = millis();
    check = 1;
  }

}