It is so much to take in in such a short time. When I was diagnosed in November so many people wanted to rush to my side and I had to stop them. You need space also to get your head around everything. It's tough. I have quickly learnt that I have to come first in this and if I'm not up to phoning people, messaging people and just want to be in my own world then that's ok and people need to accept that.
No one knows what you are feeling unless you have been there.
So no apology necessary. It was a day to embrace your who you needed to. as suggested, if you feel you need to explain maybe a letter is the way to go.
This is your journey and you need to be allowed to do it your way xxx
Look after yourself. That's whats important xxx