displaying all post categories on blog page

The blog was working fine a couple of hours ago but something has changed – I’ve inadvertently change something.
At the moment all I’m getting on my blog page (http://scotianaires.ca/news/) is one archived category (Rehearsals) – how do I get the other categories to display?
All of my posts (all 11 of them so far) are visible when I click on Posts in the Dashboard – I’ve set the filter to view all categories, show dates – but that appears only to affect the Posts list in admin. Where do I set that for the site/blog page?
How do I tell it to show all categories?

I made a new page to hold the blog and set the static front page – blog to that new page thinking I could clear whatever I had inadvertently done – but the same problem occurs with the new blog page “News”.

Very frustrating.