I thought this sounded like an interesting concept, social media has baby and things go wrong is what I got from the synopsis.
The film kind of went how I expected but lacked or even included too many things for it to be a good film.
It lacked meat on the bones of the overall storytelling from her backstory to her life in general. It included too many different characters and themes without managing to nail any of them.
It has a fairly dark dreary look which can add to the tone of a film and its not something I dislike but its done in a fairly weak manner that it never really hits you with any impact.
When the focus here is on the lead actress you really need a great lead and Noémie Merlant never pulls it off. The melancholic feels are all there but everything else is just placid. The rest of the cast ( including Kit Harrington ) are bit players and often overlooked or put in a corner once their purpose has been served. Many of which serve little purpose that really get to you in an unnerving way as intended.
You could remove a few characters and give others more to do and Im sure the impact would have been greater. I don't know an awful lot about Post Natal Depression so its difficult to comment on the realism in how it was used. Overall though it ended up being a bit disjointed and withering to a pretty anticlimactic ending.
There are flickers of horror and an ever omnipresent haunting flow to the film but little else.
5/10.