YOU SAID:

i really have to go to the bathroom but i'm too tired to.

INTO JAPANESE

私は本当にトイレに行かなければなりませんが、私はあまりにも疲れています。

BACK INTO ENGLISH

I really have to go to the bathroom, but I'm too tired.

INTO JAPANESE

本当にトイレに行かなくてはいけないのですが、疲れすぎです。

BACK INTO ENGLISH

I really have to go to the bathroom, but I'm too tired.