I hope your operation went well and that you're making a good recovery. Cancer is a tough one, my very best wishes to you.
I don't think you're being silly, you're ill, feeling vulnerable and worried and it's logical to want you family around you. In times of need it's instinctive to gather resources. So no, not overthinking, just having a feeling which is natural and normal.
But adult children, they do seem to see things differently. It doesn't mean that they don't love and care about you. It could be that they know you are being cared for, but as they can't visit at the moment due to Covid ( I'm making the assumption you're under some restrictions wherever you are), that there is no point. They know what's happening, and will leave it up to you to make contact again. It can feel horribly selfish of them. It may be, it may not be - sometimes it's just that they don't see life, support and family like we do. With mine, it also seemed to be that they thought I ought to just 'know' or I'm some kind of mind reader!
Do as much as you can to focus on yourself and getting well, and lean on your husband and friends who 'speak the same language'. Deal with the offspring when you're feeling up to it. Best wishes.