Very much emphasize with you. You've not let anyone down and please don't beat yourself up about it.I had similar experiences. Last Saturday I missed a big family occasion (my sister's 60 th),for the same reason. I have general anxiety disorder and got very stressed about journey as you did,. My IBS flared up at the start of the week and was so bad the morning I hoped to travel I went to hospital to get checked out.
That's my friends 60th as well missed,a friend's wedding,other o casinos too.
My family and friends all understand however and I understand your guilt feelings but please don't feel that way.
I'm not giving up though and hopefully have a go at visiting my sister in a few weeks.
Take care
Paul