Without looking over your shoulder it's hard, but as a first step, get your cursor to the end of your writing then on the menu press the weird looking icon that looks like a peculiar P
This will reveal all sorts of dots and arrows - these don't show on your printed doc but they indicate what you've done in terms of making new lines, spaces, etc etc
Have a look down your last blank page and see if any symbols appear there, and if they do, try deleting that symbol
Secondly, is your last piece of writing in a table? It could be that the default spacing of the table is pushing the borders of the table into the new page. Try re-sizing the table, or the text in the table, or altering the cell spacing in the table.
Hope this helps!