Is it normal that i go to sleep about 6am every day?

Since some years ago, I always go to bed very late, and of course, I wake up very late, too. I am afraid that as time passes, I go to sleep later! By now, I go to sleep about 6am, and wake up about 2pm. I always try going to sleep earlier, but I can't as my body don't tell me to go sleep.
And when I have to rise up early, the night after I go earlier to sleep (because I'm tired), but sleep for so many hours that the next day I don't go to sleep until late, again.
Is it normal?