The difference between when I am sick and when Satu is sick

Right now, Satu has a terrible summer cold. She is dizzy and wheezy and feels like crap. She will still go to work tomorrow. She still puts on clothes (something I don't even do sometimes when I am well) and she will still do lots of the things she normally does, just with a stiff upper lip and coughing the whole time. When Satu is sick, it makes her seem kind of depressed and occasionally angry at her body. When I am sick, I get scarred and insufferable.
Satu has vacuumed the house, studied her book about sailing and learned to tie a bunch of knots using her feet. This weekend I was not sick, and mostly I just dug around in the yard listening to audio books on because I didn't want to sit down and read. It takes away from my candy crush addiction which I think I may need to see someone about.
A moment ago, my sick wife put down the textbook that she was studying and pulled a splinter out of my hand and got a band aid on me. Even when I am supposed to be taking care of her, she takes better care of me than I do her. Don't get me wrong, I give it my best shot, I make soup and tea and hover around with my eyebrows all knotted up, but ultimately, the soup is not homemade and the tea cups usually have honey dripping down the outside somewhere. When Satu is sick, it makes me worry, which kind of makes me act like an asshole. I get frustrated and short tempered and worried so I dither and implode.
When I am sick, I assume that I am close to death. I am afraid that feeling mildly unwell means that worse things are on the way and that I am surely showing the first signs of a disease that will melt me from the inside out. If I feel the slightest bit nauseous, I imagine that it will only be a short time before I am reduced to a struggling desperate soul clinging to life from my puddle of bile and moaning like a creature in a haunted house. When I look over at Satu calmly reading her book, I wonder why she can be so calm. Does she have no fear at all. Then I realize that it is because she is always calm. Even when she worries, she stays in complete control. I have never seen her pace. I have never seen Satu do anything timidly. Even when she was afraid to get on an airplane during a storm, she just suffered quietly (while I offered the opposite of reassurance) and had what I imagine was a tidy, brief nervous poo. Then she gathered her bag, stuck out her chin and got on the plane.  I think that was for her the same situation that I face when I am ill, yet she sucked it up and got on with things.
Is it any wonder that I find Satu so calming, grounding and comforting? I don't know how I can do this same thing for her. I may be a very caring and attentive person, but on the inside, I am always just one firing neuron away from downright hysteria. Satu is always one firing neuron away from having an idea.
I know that she will feel better soon because she is hungry and her coughing is getting better, but I do have to keep reminding myself that if she isn't worried, I shouldn't be.