I couldn't help it.
我也没办法。

Scene
teacher: Why are you sleeping in class?
student: I couldn't help it! I hadn't been sleeping all the last night!

Notes
"I can't help it " 含有“无可奈何，我也没有办法”之意！ can't help除了这种用法外，还可构成词组 can't help doing ，表示情不自禁做某事，譬如，I can't help thinking of my lover.

Exercises
现在来看看这个句子怎么说：
我也没办法，我生来就那么美.