13 month old. Still surviving off such little sleep

[durdledoo]

I was wondering if there's some sort of sleep regression that happens about now?
My already incredibly poor sleeper has got even worse.
In fact she's never really got over the last sleep regression.
She only took 1 50minute nap yesterday, went to bed at 7 (we put her down awake, she settles herself, we go in at intervals if she's upset and calm her before putting her back in her cot) and she was up at 12, drained a 8 oz bottle (this doesn't happen every night but she was certainly hungry!) and then woke up at 3, refused to go back to sleep and had since had a 30 minute nap.
What are we doing wrong?
We make sure she is settling herself, sure she isn't happy about it but we don't leave her to cry for prolonged periods of time. She has most certainly got a whole lot worse since we after Christmas (this whole thing started whilst we were in our Xmas holiday) and I can't help but feel I've exhausted my options other than ear defenders for the rest of the family.
Any tips? Am I alone in this prolonged sleep deprivation?

Is she teething? Does calpol make her sleep ? If yes just give some in the night.
Fresh air in the day, either a walk out in buggy or run round park.
Does going to bed later work? Mine doesn’t go to bed until 9 so he wakes up later.
Does a nap improve the night time sleep or is she better without a nap?
Do you get plenty get of food in her during the day? Would porridge or baby food at bed time make her sleep longer?
Is she cold?
I’ve got a bad sleeper mines 18 months old. He sleeps in my bed which increases my sleep. We were doing ok until he started teething again a few weeeks ago and he wakes up between 4 and 5. Above is the list I go through when he’s not sleeping until I find what works.

I'm not sure, she has 12 teeth soo probably! She's been teething forever I believe.
We struggle to keep her up later, it's a vicious circle and when she has gone to bed later it's due to a later nap, she always has 1 nap at least, I haven't noticed less/more helping with sleep.
She's had 1 nap today after the most horrendous night I don't know how she manages it.
Feel like bringing her into bed with us too but just remember the earlier co sleeping days, she got easily distracted by me being there and thought it was playtime.
I think a growth spurt is definitely occurring, she's eating a lot! I tried readybrek bottle and bed and she ate too much and threw up everywhere. Have tried again tonight but will space out more and see if it helps.