Oops, I was dozing off during the lecture. 哎呀，我在讲座上睡觉了。

I didn't catch any of it. 我什么都没有听到。

Now, I'm gonna fall way behind. 现在，我会跟不上别人了。

to doze off=to fall asleep

I didn't catch any of it. =I don't understand.