Entire site gone after update – new to WordPress

Hi.

I foolishly updated themes, plugins and the WordPress version yesterday and my entire site crashed. I am reasonably sure it was the version update that did it. Cannot get to the admin or any menu for that matter. address is blog.bostonsight.org

I have read many posts about this topic, but I am only the person who uses the CMS, and not the person in charge of the back end of the blog. I don’t even know who that might be – I inherited the blog from a former co-worker who passed away recently. All I have ever done until yesterday was to post blogs. I have never backed up.

None of the advice given to others makes sense to me, as I don’t know how to go somewhere to disable plug ins, for example, or where I would even go to do that.

We have a website (www.bostonsight.org) and a microsite (providers.bostonsight.org) – is it reasonable to think that the same people who host those sites would also host the blog? Do such people regularly perform back ups?

I don’t even know what my question is, other than what do I do now? Sorry for sounding like a moron, and clearly I am one for not having thought about any of this prior to clicking update, but any direction anyone could point me in would be helpful.

Thanks.