Galaxy S5 home page has moved

Not sure if this should be in the Android section or the Samsung section, so I'm starting here because it seems to get more footfall.

Some while ago the little home symbol that's usually the first of seven little dots near the bottom of my screen (sorry, I don't know what the correct term is, but the dots indicate which of the seven available screens I'm looking at) move to the fifth position instead of the first. So whenever I press the home button I get the fifth page, which happens to be blank. To get around that I dragged all my home page icons over to the fifth page, but I'd really like to get the home page icon back to its proper position in the line, and can't find any way to do it. I've tried holding the symbol, to drag it the same way I can drag and place icons, but all it does is display what page it is.

Any ideas please? My phone's running Android 5.0, but the issue has existed since before then.

tag: Samsung Galaxy S5 , free mobile games download