In your Word doc, can you see the formatting symbols (dots for spaces, etc?) Can you tell if your hard paragraph break (a paragraph mark) have somehow gotten replaced by a soft break (looks like an arrow that goes down and then left.)?

Also, were you copying and pasting from another document or an email or to/from googledocs? (If someone is betaing for me on the fly, I'll be sending them bits and pieces however I can.) Sometimes the paragraph breaks get messed up in the back-and-forthing.)

If you're posting with a client or in RTF mode, maybe try switching over to the pure HTML posting mode and see if it catches the breaks that way (but watch in case it loses other formatting like bold/italic/underline.)