6 months old is still quite young, and it's hard to hold her bladder for such a long time overnight.
Also, since she has been recently spayed, things may "feel" differently for her and she may not recognize the signs as well herself, for when she has to go pee.
Best suggestion, set your alarm clock for 5:30am, and take her out to go pee first thing in the morning. Then over time, you can slowly start to set your alarm a little later in the morning.
As other said, limiting her water before bed time is also very important.
Best of luck with your young pup!
Timber - Siberian Husky - 3 yrs old
Jasper - Siberian Husky - 3 yrs old