Hi! Many hugs! Sounds difficult! Hang in there- sending all the positive vibes
That many night wakes I would def tie to discomfort. Maybe lessen the amount of solids you are giving her? I would also not rule out teeth as they start coming around this time. Try medicating before BT.
However, I think your routine can also use some tweaking that can hopefully help improve some of the NWs over the course of a few days/weeks.
First I would def consider increasing her A times. Here is a link for average A times and for her age your looking at 3-4 hrs between naps. Also, by now many are down to just 2 naps a day. As you steadily increase her A times, she will drop to 2 naps and over some time as she adjusts, her naps will lengthen as well-- pushing out that last nap.
Average A times- BOOKMARK ME! I'm assume if she's falling asleep in the car it's for short bits at a time? ...she's prb OT in her day which also ties to NWs but short A times in the day can also cause UT NWs too... Which in return give you OT days. It's weird haha but she might be in a OT/UT loop and working on her schedule can help sort out her nights some too. Won't happen over night either- consider gradually pushing her A times, when possible, by 10/15 mins at a time for a few days. Hopefully you all adjust smoothly.
Here is a link worth looking over on sample routines for her age. It can help give you an idea on what to expect more or less for her age. Every baby is different but this is a good guide if you need some help on routines
they help me out sometimes!
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chronological EASY samples, 7-9 monthsI know things can be complicated with other babies in the mix, and sometimes you can't do much but accept the OT for the older children's activities and such. Weathering the storm so to speak and know that eventually she will stay awake longer and it will fall into a better place. I have an older one and sometimes routine goes out the window.
Many hugs xo!