YOU SAID:
I had to go to the bathroom after lunch.
INTO JAPANESE
私は昼食後にトイレに行かなければなりませんでした。
BACK INTO ENGLISH
I had to go to the bathroom after lunch.
INTO JAPANESE
私は昼食後にトイレに行かなければなりませんでした。
BACK INTO ENGLISH
I had to go to the bathroom after lunch.
That didn't even make that much sense in English.