Does it upset you when Christians or anyone else, who doesn't know the whole story, tells you not to worry?

I've got a fab group of friends, who I absolutely adore. They are Christians and I know as Christians God tells us "not to worry." They've just told me I worry too much - regarding my health. I can take it when I'm worrying about other things, but not when my worry is all too real. God alone knows all I've been through and He knows what I've got ahead of me in the coming days/months and it's like telling someone who's just been diagnosed with cancer, not to worry.