I have a fixed retainer & normal retainer yet the gap in my front teeth has come back?

I wear my plastic retainers every night, and everything was fine until a few days ago the gap between my front teeth has come back. I have no idea what has caused this and I have no idea how to stop my teeth from moving anymore. Will I have to wear my top plastic retainer all day to stop any further movement? Even though I have a wire across my two front teeth which was was meant to stop this from happening (fixed retainer). Any help?