sonia,
i HATE this for you. i think i know where you're coming from partially. last time before i got a cold (which turned into an exacerbation) i was exercising daily at my highest stamina ever--45 mins cardio 4-5 days a week. i was at the top of my game! i thought surely with my lungs in great shape i'd make it through that cold alright. but i didn't.
so i hear ya. it doesn't seem fair that with all we do to stay healthy then something can just come along and knock us down so hard. my thinking was if i hadn't done all that exercising, i may have hit an even lower low getting sick, or maybe i would not be able to build myself up as much afterwards. we've got to rationalize it somehow, eh?
all i can say is, it just gets harder and harder the older we get. you and i are about the same age and i am realizing this past year especially how fragile my health is. ah, it sucks.
i hope you feel better soon. that anxiety and nausea seem really awful.