Please help dont wanna lose my work

Hello friends, I need your help I have been working on a web page and I dont know why, but in one of the pages everything went blank and in the preview it only says "Sorry, we can't find this resource." the other ones are ok ! how can I recover the work ?. NOTE: I was working on another page and when I went back to see the other pages one of them went blank . I didn't delete anything only created an iframe in a different page.