I think the first thing that you need to do if fix the formatting on one of your posts that is messing up everything below it. This is most often caused by an open HTML tag in one of your posts.
Go to settings > writing and select "WordPress should correct invalidly nested XHTML automatically" and then click "save changes."
Now, starting with I was looking f…, open it in the editor, make one minor change such as adding and then deleting a space, and then click "update post." Check your blog and if it is back to normal, you are golden.
Post will be in reverse chronological order (newest at top). There is no way to change that. It might be that everything will go back to normal once you have the HTML error issue fixed.