Its depressing to say, but likely give it a day or two, hit reset a bit in terms of tactics, and start playing and you will suddenly be back to your better level again.

Unless you are really good at this game, the inconsistent gameplay just makes you go up and down like mad. I went from Div 6 to Div 3,over the course of a week, then suddenly couldnt buy a win - same players, same tactics, same play style.