Bloody sucks. I remember saying exactly the same thing when I was diagnosed, I wish it would just all go away. That's almost a year ago now.
That feeling will pass, to be replaced by others, some crap, some better. Right now, do what you can to distract yourself. Stupid tv sitcoms were the only thing that worked for me. Exercise, work, gardening, the company of those who make you laugh, whatever works for you. If you're that way inclined, meditation can help. It puts a space between you and your thoughts. I use Headspace via an app on my phone.
When it all threatens to overwhelm, take some slow deep breaths. Try 4-7-8. In for four, hold for seven, out for eight. Do this five times. It will help calm your nervous system which is currently totally overloaded.
And tomorrow, give the BCNA helpline a call. 1800 500 258. The wonderful folk there are a tremendous resource and fantastic listeners.
Hang in there. Big hug, K xox