My 7.5 month olds sleep is all over the place, very unpredictable! Most nights she will go to bed between 7 & 8 and wake up around midnight/1am, then back to sleep until anywhere from 4-6am! Although, last night she was in bed at 8 and woke at 2am! I don't think there's anything more i can do tbh, it's developmental and she will do it when she's ready
I'm sorry I hope I can give you advice but I'm on the same boat as you. There are nights when my son wakes up 3x, and that's fine for me. Other times he'd wake me up almost every hour and it's harder for me to go back sleep and what's worst is when I'm about to sleep or had drifted to sleep for maybe 10 mins he'd wake me up again for a feed( he is nearly 22 months and is breastfeeding still) he was late with teething so now every month simultaneously a molar and teeth arrives and I know the feeling. It's even harder for me because all night and all day I am with him as I'm staying home for now and left job to take care of him and husband is at work on days so I totally got your frustration. I had doubled my size in weight pre pregnancy as the lack of sleep somehow compromised other system or aspect of the body so I tend to eat a lot and not dieting for now. It's hard I know I have been sleep deprived for nearly 22 months now.