Me too.
Mine seems to have come about because for the best part of a year ds woke around this time and I used to have to bribe him with boob to go back to sleep.
Now he doesn;t wake anymore but rather infuriatingly, I still do. And yes I am also quite awake but not so I'd want to get up. Sometimes takes an hour to get back to sleep by which time ds is usally waking. Grrr.....
The light mornings & birdsong don;t help.
Have you got blackout linings?
I find going to bed just a bit later does help.