@Moonshine160
Oh wow, I have been searching mums better for a post just like yours as we are in the EXACT same position! You may have read my post on the sleep forum of mums net recently too!?
Our daughter was also a fantastic sleeper for ages and slept a full night between 7-7 and then all of a sudden when she turned 2years old, she just wouldn't go to sleep without me being there next to her . We have also been thinking it is separation anxiety .
I sit with her whilst she goes to sleep at 7pm. Depending on the sort of day we have had , this can take 20mins , it can take 1 hour !!!! I started off sitting next to her cot , and then over time I now sit next to the door . I then make my escape. But around midnight-2am she wakes screaming snd shouting "oh no". I tried repeating sitting next to her again , but like you said in your post , it can take her hours to actually go back to sleep , it's like she's ok such a light sleep! So if I make my escape after a while, she immediately knows and screams such a high pitched scream again. It's impossible to stay sitting in her room throughout the early hours or the night
We are SO tired too, so we've resorted to taking in a camp bed into her room when she wakes after midnight . I worry so much that she is getting used to this and will rely on it, but there's nothing else we can do as we just need to sleep!
I would love to connect with you and chat more if you would be up for that ! I have no idea how to do that over Mumsnet though ! I've seen people say about private messaging but I don't know where that is on the Mumsnet app!!
Anyway, sorry for the long post and the fact I couldn't help at all but I hope my empathy helps a bit to know I am also going through the same at the moment !