[SOLVED] Line breaks in post content field?

For some reason, when I compose a new post, line breaks aren't being preserved.

So I type a couple of paragraphs, and when I view the site, everything combines into one huge paragraph (in both FF and IE).

So I go into HTML and use <p> and </p>, which works great, but if I go back to the Visual editor to make any changes, all of the paragraph marks get removed and it's back to one big paragraph.

Help!

website is samanthabrandtphotography.com