(solved)could use help with POV-clock code (trouble with even starting correct timing......)

int const outpin = 13;
volatile int state = LOW;
int reading;
int previous = LOW;
volatile long previousmillis = 0;
volatile long starttime;
volatile long elapsedtime;

void setup() {
    pinMode(outpin, OUTPUT);
    attachInterrupt(digitalPinToInterrupt(2), blink, CHANGE);
}

void loop()
{
  reading = state;                                       //read state
if (reading == HIGH && previous == LOW)                 //if state is detected
{
  detachInterrupt(2);                                   //first, disbale interrupt to enable calculations
if (state == HIGH)
starttime = millis();                                  //starttime is taken from millis, which counts all the time at background
}
previous = reading;                                    //take previous from current reading
elapsedtime = millis () - starttime;                  //calculate time; millis is bigger than starttime
if (elapsedtime ==0 && elapsedtime <= 4)           //turn led on between 0-4ms
{
  digitalWrite (outpin, HIGH);
  }
  if (elapsedtime >=4)                               //turn led off at 5ms
  {
  digitalWrite (outpin, LOW);
  }
  attachInterrupt(digitalPinToInterrupt(2), blink, CHANGE);  //after calculations, enable interrupt
  }

  void blink() {
    state = !state;
}

int const outpin = 13;                     //output for darligton array, turns on led-strip
volatile int rotationmade=false;
volatile int reading;
volatile unsigned long starttime;
unsigned long elapsedtime;
unsigned long difference;

void setup() {
  pinMode(outpin, OUTPUT);
  byte const rotation = 2;
  attachInterrupt(digitalPinToInterrupt(rotation), blink, CHANGE);
}


void loop()
{
noInterrupts();
reading=rotationmade;
interrupts();


if (reading == true)
{
digitalWrite (outpin, HIGH);
}

elapsedtime = millis() - starttime;
if (elapsedtime >=5 )
{
  digitalWrite (outpin,LOW);
  rotationmade = false;
}
}



void blink()
{
    starttime = millis();                           //set starttime as current millis each rotation
  rotationmade= true;                               //rotation is made
}

int const outpin = 13;                     //output for darligton array, turns on led-strip
volatile int rotationmade=false;
volatile int reading;
volatile unsigned long starttime;
volatile unsigned long elapsedtime; // there are interrupts so we need to make sure there saved
volatile unsigned long difference;   // these too

void setup() {
  pinMode(outpin, OUTPUT);
  const byte rotation = 2;  //was wrong byte after const 
  attachInterrupt(digitalPinToInterrupt(rotation), blink, CHANGE);
}


void loop()
{
noInterrupts();
reading=rotationmade;
interrupts();


if (reading == true)
{
digitalWrite (outpin, HIGH);
}

elapsedtime = millis() - starttime;
if (elapsedtime >=5 )
{
  digitalWrite (outpin,LOW);
  rotationmade = false;
}
}



void blink()
{
    starttime = millis();                           //set starttime as current millis each rotation
  rotationmade= true;                               //rotation is made
}

byte const LEDoutPin = 13;      //output for darligton array, turns on led-strip
byte const rotationSensor = 2;  // sensor detects one reference mark on the disk

volatile boolean rotationFlag = false;
volatile unsigned long starttime;
unsigned long sensorDetectTime;

int LEDstate;

void setup() {
  pinMode(LEDoutPin, OUTPUT);
  attachInterrupt(digitalPinToInterrupt(rotationSensor), rotationSensorISR, FALLING); // or RISING depending on hardware.
}

void loop()
{
  noInterrupts();
  boolean rotationStarted = rotationFlag;
  interrupts();

  if (rotationStarted == true)
  {
    digitalWrite (LEDoutPin, HIGH);  // turn on led when cycle starts
    LEDstate = HIGH;
 
    noInterrupts();
    sensorDetectTime = starttime;  // record the sensor time stamp
    interrupts();
 
    rotationFlag = false;  //acknowledge interrupt by resetting the flag
  }

  if ( micros() - sensorDetectTime >= 5000 and LEDstate == HIGH )
  {
    digitalWrite (LEDoutPin, LOW);  // interval is over, turn off LED
    LEDstate = LOW;  // remember LED state so we only turn it off once.
  }
}

void rotationSensorISR()
{
  starttime = micros();                           //set starttime as current millis each rotation
  rotationFlag = true;                              //rotation is made
}