Sorry I'm not feeling to sympathetic ATM. I have a 3 yr old, 2 yr old, an 9 week old. I'm up at least 5 times a night because they all seem to tag team each other in the wake up department, and my 2 year old generally starts the day between 4 & 430 am.
I think 11 hours over night, straight btw, is a pretty decent sleep for anyone. Yeah 6am might not be ideal, but I'd take it while it's there, because in another month your bub might be up a few times a night an waking earlier. Unfortunately there's not much advice I can offer, because I can't remember the last time I slept through the night, let alone 11 hrs straight.
I'd also just start going to bed a little earlier if you're not getting quite enough sleep.