Building a Days Counter with Arduino Leonardo and an RTC 3231 - arduino-uno

Question

I've been trying to create a days counter that starts counting from a unix timestamp. I'm using an arduino Leonardo, an RTC DS 3231 and a 7-segment serial display(by microbot). Here's the display link: Serial Display Link
But I cannot get the display to print ny output. I think I might have messed up with the connections.
I have connected the Vcc and Gnd from the rtc to the 3.3v and gnd of the arduino and the Sda and Scl to the Sda and Scl of the arduino.
For the display I connected the Vcc to the 5V, the gnd to the gnd and the Rx to the digital output 5( Is this correct? I know I have messed up sth here)
Here is the code:
#include <Time.h>
#include <TimeLib.h>
#include <SPI.h>
#include <Wire.h>
#include "Adafruit_LEDBackpack.h"
#include "Adafruit_GFX.h"
#include "RTClib.h"
RTC_DS1307 rtc = RTC_DS1307();
Adafruit_7segment clockDisplay = Adafruit_7segment();
int hours = 0;
int minutes = 0;
int seconds = 0;
unsigned long previousMillis = 0; // will store last millis event time
unsigned long sensorpreviousMillis = 0; // will store last millis event time
unsigned long fiveMinuteInterval = 300000; // interval at which to use event time (milliseconds)
unsigned long postDaysInterval = 7200000 ; //seconds in a day 86400000
#define DISPLAY_ADDRESS 0x70
unsigned long theDateWeGotTogether = 1441843200; //in unixtime
unsigned long days ;
int weeks ;
void setup() {
Serial.begin(115200);
clockDisplay.begin(DISPLAY_ADDRESS);
rtc.begin();
bool setClockTime = !rtc.isrunning();
if (setClockTime) {
rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
}
}
void loop() {
// DateTime now = rtc.now();
days = ((now() - theDateWeGotTogether) / 86400); //86400 is the number of seconds in a day
unsigned long currentMillis = millis();
ShowDaysReading();
time_t t = now();
if(currentMillis - sensorpreviousMillis > fiveMinuteInterval)
{
// save the last time you performed event
sensorpreviousMillis = currentMillis;
DateTime Zeit = rtc.now();
}
}
void ShowDaysReading()
{
days = ((now() - theDateWeGotTogether) / 86400); //86400 number of seconds in a day
weeks = ((now() - theDateWeGotTogether) / (86400 * 7) ); //86400 number of seconds in a day
clockDisplay.print(days);
}