Thanks guys for all the comments.
I was supposed to see my other sister down in Sussex. Probably still will go. As you say, why let someone effect my plans. Just an exacerbation of my symptoms as I was improving until then. I get social anxiety always, even when seeing members of my family who I like. The worse the depression is the worse the SA. I'm quite a loner and find relationships complex and stressful which is a big issue.