For me, it was a frightening time with so many unknowns. Like many, I saw the time of diagnosis as a risk to my comfortable, in-control world. I was flooded with thoughts about the reality that my life may be limited and that I was no longer in control. I literally needed to remind myself to stay within the now and told myself, "You are safe and nothing is happening to you at this very moment. Use this time to grieve and also find gratitude for the life you have."
The best advice I can give is to be gentle with yourself. If you need to be alone, so be it. If you need to be surrounded by others, take to the phone and ask for the support you need.