Yesterday evening I visited my blog and it was operating problem-free. A couple of hours later in the same evening I visited the blog again, but this time I couldn't establish a connection due to a "database error." This morning I can access the blog - in the admin panel I can view statistics, widgets, etc., but the posts and comments do not appear. No error is mentioned. The content just disappeared. What should I do to resolve this? No administrative changes were made to the website yesterday evening or this morning.