9 month old suddenly HYSTERICAL at bedtime, feel like world's worst mummy

[Renard]

LONG - sorry...

So my DD has just hit 9 months, and overnight has a major issue in the evening. She has historically been a pretty good self settler, barring teething and 4 month sleep regression. Nothing in her routine has changed - apart she has suddenly cut her lunchtime nap short by half an hour.
Anyway, the last few nights she has been a nightmare when going to bed, lying down calmly with her comforter and dummy, but then starting to sob the minute I leave the room. The minute i return and settle her she calms, the minute i leave she sobs - this builds to hysterics. Last night I sat outside her door and went in every 3/4 minutes - patted and calmed and walked back out. She was shouty crying, and sometimes drifting off, but if i felt she building to hysterics I would go in pat her until she was calm (which didn't take long at all) then tiptoe out. After 40 minutes of this (she had fallen asleep a few times) I heard my mobile ringing and went to grab it (DH is abroad at the mo), I whizzed back because i heard her crying and she had been SICK! Obviously I comforted her, cleaned her up. By then she was exhausted and fell asleep wih me rubbing her back.
I don't know what to do!?? I feel like the worst mother in the world: utterly horrendous that my leaving her caused her to be so upset that she threw up. I was trying to help her without rocking her to sleep etc... ARGHH. Of course I felt so awful that I didn't sleep a wink, and would love some advice.
I don't want to undo all her self settling but clearly what I am trying to do is not working. (Though I should mention that the night before she was also very upset - this has been going on for about 5 nights - and she fell asleep in the end after I went in every 4 mins) But obviously I can't ever let her get so distressed again.
Am pretty sure it is not teething, she cut 4 teeth in 10 days about 5 weeks ago, and the signs are different. I also don't think it is hunger as she eats well all day.
Please if anyone has ANY advice I would appreciate it, I feel like a devil mummy this morning... :(

It's developmental. It's better known as the 9 month sleep regression. Most children go through this developmental stage at this age. It's usually when they're working on huge leaps like getting up and moving towards walking. Their brains are unable to switch off and self settling doesn't work for them. They find it extremely distressing. The only comparison I can make is it's like when you start a new and tough job. You lie awake with your mind whirring and you're exhausted but it keeps going round and round and round. Or an exam looming. Except we can rationalise it. They just know that their body and brain is buzzing. You also find that 9 months is the key time for separation anxiety so they really struggle with you not being there. I just did whatever I needed to in order to get through it and you generally find that once the developmental leap is over, good sleepers and self settlers go back to old habits.

The above all assumes of course that it's not teething and she isn't poorly. There is every chance that she's under the weather and this too can account for the being sick.

More info here.

showofhands. Thank you. being able to label it makes me feel better :) no seriously - i want to understand what is going on with her and that helps a lot. She has also started waking after 45mins at naps (like when she was a wee baby!) which I presume is all part of it.

I think one can ride anything out if you have some clue about what you are dealing with.... ARGH.

I know exactly what you mean. It's so much easier knowing that it's all normal. Otherwise you're standing in the dark at 3am thinking 'what? somebody just tell me what I'm missing for the love of God'.

The nap thing is typical sleep regressive behaviour. She'll probably drop a nap entirely soon.

slightly dreading your answer to this question - but how long did it last showy? thanks for making me feel more sane.

Exactly the same happening to my 9 mo ds.also started. waking at between 4 and 5 and not going back. Rotton!

About 3 weeks.