Hi OP, I don't really have any advice but didn't want to read and run. ❤️
I'm so sorry you're going through this. You deserve not to feel lonely and you definitely shouldn't be going through this on your own. How far along are you?
Is it possible your partner's struggling now that the baby is so close? It's frustrating but sounds like this is something going on with him rather than you. It sounds a bit like it's just hit him what this entails. He should be there for you but this may be difficult if he's feeling overwhelmed.
(Of course, he could just be a dick - I'm not making excuses for him. He clearly doesn't know how lucky he is if he can't look up from an iPad to talk to you.)
I'd try and talk to him again, explain that you feel like he's mentally checked out of the relationship and you feel stuck. I'd try to avoid blaming and emphasise that you're struggling to cope with doing this on your own. (Which is totally reasonable!!)
Please be kind to yourself ❤️ Have you spoken to your midwife? Is there someone at work you can chat to, or a neighbour? Anyone on his side of the family?
On a side note, have you got anything you do just for you? Like going for a short walk, reading, anything like that? Something positive you can do on your own. It obviously won't fix anything but your mind may be clearer after half an hour of walking outside in the fresh air. xx