This effect should only happen if you accept the professor's injection. And at some point afterwards you should get (very powerful) special attacks that draw on and reduce your lust so that you don't get overpowered by it (though you'll still occasionally loose a turn due to dizziness)—they'll appear as cards in your hand only when your lust reaches a critical level. However, I'm not sure exactly what gives you access to those attacks: you probably need to succumb to lust in at least one battle (possibly several), and perhaps buy some other upgrade from the professor or take additional combat training. Avoid boss battles until you have access to those attacks.
But of course, this is what should happen, and the game is buggy enough that it might very well be that something has gone wrong in your playthrough.