Your time on fire per 10 minutes is 1:03 for season 10. See the small text. 4:52 is most time on fire in a single game.
To your original question, inactive accounts are subject to very large moves when you return. Season 9 Placements Analysis, High Variance Explained
I suspect that the order of wins and losses is highly significant, much more significant that statistical performance. Did you write that down / remember it for the 15 games?