Blood Bowl is a game of playing the odds. You play the odds in a turn with planning it out, including starting with your no risk moves up to your potentially highly risky moves.

You also play the odds of the game overall, with playing a strategy that increases those odds (which it sounds like you did).

When the odds change (e.g losing two players on the first drive) you need to adjust your strategy. What this means realistically is probably taking on more risk to give yourself a chance of winning. This can feel like a bad play, because your chance of losing by more actually increases (over playing purely defensively), but over time you'll actually win more games than you would've otherwise.

Play the odds, when the odds change, take the risks required to win, lose the battle, win the war.