BT Yahoo is my home page. Along the top is a "Bookmarks" drop down menu and below that are various icons, one of which is a "book"= "bookmarks". It is this one that I usually use - and even recently "bookmarked" web pages disappear. The top "bookmarks" doesn't list them either.
It would appear that the only way I can access my bookmarks is via the "edit" function. I really don't know why this should suddenly happen.