When I create a new page it over-writes all other pages!

I have created an 'about ' page (www.melaniemay.com/information) and saved it. Then I created a photography gallery page and saved it. My about page is now showing the exact same content as the photography page. I have created three seperate photography pages and they all show the same content even though I created them and saved them with different content. I have lost all the work I have done over the past three days. Can you please tell me what I am doing wrong as I am following all the instructions I can find!

Thank you