I think one of the hardest things to come to terms with is never knowing why. I researched, read medical journals, bought books, had a gp appointment to discuss it, they carried out a post mortem and then we had a consultant appointment to go through the results and it was all for nothing.
It's such early days for you that you will go through so many different emotions each day. It's the process of grief and it does get better and you will be less numb and exhausted and drained by everything.
As for your MIL I would steer clear for a while and also from anyone else you doesn't make you feel comfortable. That's your DP's job right now. He's your barrier between you and the rest of the world. Don't worry about offending anyone. It's all about you now and sod everyone else.
It was weird who I felt comfortable around. My absolute dearest best friend meant well but I was always offended by what she said. She'd be mortified if she knew but I just avoided her for a while to keep myself safe. I had two safe friends who had been through similar circumstances.
I had friends who wouldn't even acknowledge what had happened and I felt so angry at them. Looking back they just didn't know how to handle it but again it was best to avoid them for a while for my own sanity.
It's a year and half since and I'd say I'm pretty normal now. I do still cry now and again and talking to you or anyone else who's gone through it does bring it all back but I don't want to forget as it will always be a huge part of my life.
See how you feel going forward for getting pregnant again. For some it's what keeps them going but you are so right in that you will never feel safe in the pregnancy until that baby is in your arms. It's drilled into us that after 12 weeks it's pretty much plain sailing but it's not for so many of us.
There are Mumsnet threads for people trying to conceive after loss and they were very helpful and supportive of that's the road you do go down.
But for now just get through this day however you can. It's sunny here in Wales so hopefully it is where you are and you can get some vitamin d in you. X