6 month old suddenly can't settle during the night

[Chocolateyclaire76]

My LO has self settled for nap and bedtime since 3 months and during the night would wake twice for food and then fall asleep.

For the last few nights she has been waking up, not wanting milk and being unable to self settle. She was awake from 3-5am last night! Tonight she went to bed at 6.30 and then woke at 8.30, inconsolable.

I just don't know how to get her to self settle at night when she can do it in the day!