What matters is that she needs support NOW and her DH just isn’t there to give her some, as she would have expected him to do when she is ill
She isn't actually ill at present though, as I understand? So her Dh is reacting as if they've had a tiring and difficult day, where he just wants to get home for the day. o/p seems to be reacting as though she's been told she is terminal, is planning how to deal with her death, and is expecting her husband to know this without being told.
She talks about "we need to eat" as if the've had some huge shock, in the same way people often advise hot sweet tea in times of crisis, as if they need to bolster themselves for hard times. Then not picking up the kids and "talking" again as if they've had a massive disclosure.
It's clear o/p has a completely different viewpoint to her DH, and both are reacting to the level of perceived seriousness of o/p's illness.
o/p needs to communicate her level of worry. She could have started a conversation at any point, rather than trying to engineer a formal "talk" and/or wait for her DH to ask.
Likely he is simply thinking the same as most on here, o/p os going for tests, it could be something serious, but she's relatively well at the moment, let's cross that bridge when we get there. o/p has self diagnosed already and is planning a severe decline and death, which the dh knows nothing about!