How do I get new Database changes since last login using Django and Python?

Question

I need to get database changes for a user, but only the updates of the user since the last time they logged in. I will be passing in just an email. I have looked into session data but none of that looks very helpful to me. I am new to Python and Django and I have no idea where to start, any help would be appreciated. Here are my models:

class Device(models.Model):
  serial = models.CharField(max_length=16, null=False, unique=True)
  publickey = models.CharField(max_length=44, null=False)

  def __str__(self):
    return '%d: %s' % (self.id, self.serial)

class Pairing(models.Model):
  device = models.OneToOneField(Device,on_delete=models.PROTECT,blank=False, null=False)
  pairingcode = models.CharField(max_length=10, blank=False, null=False, unique=True)

  def __str__(self):
    return '%s: %s' % (self.device_id, self.pairingcode)

class UserDevice(models.Model):
  user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT, 
null=False)
  device = models.ForeignKey(Device, on_delete=models.PROTECT, null=False)
  activation_date = models.DateTimeField(default=timezone.now, null=False)
  friendly_name = models.CharField(max_length=20, null=True, blank=True)
  is_owner = models.BooleanField(null=False, default=False)
  is_admin = models.BooleanField(null=False, default=True)
  is_alerts_enabled = models.BooleanField(null=False, default=True)

  class Meta:
    unique_together = ('user', 'device',)

  def __str__(self):
    return '%s => %s on %s' % (self.user.email, self.device.serial, 
  str(self.activation_date))

class Schedule(models.Model):
  device = models.ForeignKey(Device, on_delete=models.PROTECT, null=False)
  time = models.TimeField(null=False)

  class Meta:
    unique_together = ('device', 'time')

class PendingSchedule(models.Model):
  device = models.ForeignKey(Device, on_delete=models.PROTECT, null=False)
  user = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.PROTECT, null=False)
  time = models.TimeField(null=False)

  class Meta:
    unique_together = ('device', 'time')

class Tray(models.Model):
  device = models.ForeignKey(Device, on_delete=models.PROTECT, null=False)
  slot = models.IntegerField(null=False)
  full = models.BooleanField(null=False)
  time = models.DateTimeField(null=False)

  class Meta:
    unique_together = (('device', 'slot'), ('device', 'time'))

  def __str__(self):
    return 'Cup %s of %s %s' % (self.slot, str(self.device), "Full" if 
  self.full else "Empty")

class TrayStatus(models.Model):
  device = models.ForeignKey(Device, on_delete=models.PROTECT, null=False)
  slot = models.IntegerField(null=False)
  reason = models.TextField(blank=False, null=False)
  time = models.DateTimeField(null=False)
  recorded = models.DateTimeField(auto_now_add=True, null=False)
  expectedTime = models.DateTimeField(null=False)

class CheckIn(models.Model):
  device = models.OneToOneField(Device, on_delete=models.PROTECT, null=False)
  time = models.DateTimeField(null=False)


class UserProfile(models.Model):
  user = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.PROTECT, null=False)
  token = models.TextField(null=False, blank=True)
  first_name = models.TextField(null=True, blank=True)
  last_name = models.TextField(null=True, blank=True)