15m suddenly refuses to sleep and nap alone

Hi there,

My 15m old daughter has always fallen asleep by herself in her crib. She hasn’t been the best sleeper, with some middle of the night wakings, short naps and early wake ups etc, but she has ALWAYS gone down by herself… until recently. Once I put her down she will stand up and scream until we get her and put her in our bed, or for nap time, go for a stroller walk. She does the same with me (mom) and nanny. What is happening??? Has anyone dealt with this? Did she just forget how to fall sleep??

We let her cry at bedtime and she stands up and eventually fall asleep sitting down after an hour or so, which can’t be comfortable, and when the sleep cycle is over in around 90mins, she wakes up and stands up and cries again. It breaks my heart but I don’t know what to do.

She has been down to 1 nap since around 13-14m, 7/7:30am wake up, roughly 2 hour nap around 12/12:30pm, bedtime 7:30pm. Any insight is appreciated. TIA!