YOU SAID:

I was so tired this morning, I fell asleep during Chemistry class.

INTO JAPANESE

今朝はとても疲れていたので、化学の授業中に眠りにつきました。

BACK INTO ENGLISH

I was so tired this morning that I fell asleep during my chemistry class.

INTO JAPANESE

今朝はとても疲れていたので、化学の授業中に眠りに落ちました。

BACK INTO ENGLISH

I was so tired this morning that I fell asleep during my chemistry class.