Thanks for writing in.
I understand your concern.
If you are young and healthy, then it seems like you are experiencing a lot of stress
which in turn is leading to anxiety
. I am sorry for your sister but you would have to let it go. This however does mean that you need to be slightly cautious in terms of getting the screening tests done on time.
I would suggest you see your treating physician for the time being. It looks like an anxiety disorder and he would be able to help you understand your symptoms and prescribe some medication for the anxiety.
Meanwhile, focus on the positive aspects of life; a little deep breathing and yoga
will also help.
Hope this helps