I had it happen with all the "right things " I could think of, in a cot, everything.
I think there are two different pains, guilt, and losing your baby.
Once you've got the report, the guilt will gradually go, and maybe you can take some solace in the fact that he was with you, and that actually being in your arms was a blessing iyswim.
It will take a long time for you to come to terms with losing your child. Yes, having another older child is the only distraction sometimes, just take it one step at a time.
Feeling physically sick is a shock thing I think, and you need to keep eating very small snacks of nothing else. Even something like squash would be good.
You and your dh need someone to talk to, and quickly, because you need to make sure the blame thing is stopped right now.
Your not going to get through this as a couple unless you can support each other.
Btw, have you already been in touch with your GP? They may offer you a prescription if some sort, which would be sensible. If you feel at any point you are thinking of harming yourself, please PLEASE just get help.
3 days is still so recent.
I'm so sorry, it is the worst situation possible, and ultimately, the only thing that makes it bearable is time. Allow yourself to just float through the hours, days, weeks, and in tiny tiny stages, you will feel better able to cope.