I am sorry you are here - being on this website does make it more real I know. You are going through totally normal emotions - it just feels like you will wake up from this weird dream/nightmare but you never do. 3 weeks in means you’ve barely processed the diagnosis and everyone else’s shock keeps you busy reassuring them and holding it all together. We all understand your feelings and can only reassure you that while there will be fearful, lonely days and nights, there will come a time when you settle in to this new normal and a plan of attack will help a lot. Let it all out on here to us who have walked this path before.
Sending a warm hug and best wishes.