New posts only show 'similar posts'

Previously created pages display properly:
http://www.iamstoo.com/blog/?p=29

However anything I create now comes up like this:
http://www.iamstoo.com/blog/?p=70

I think the only change I have made is to settings>
WordPress address (URL)
and
Site address (URL)

Could this have affected it?

Many thanks for your help!