YOU SAID:

I think I am going to go use the toilet.

INTO JAPANESE

私はトイレに行くつもりだと思います。

BACK INTO ENGLISH

I think I'm going to go to the bathroom.

INTO JAPANESE

私はトイレに行こうと思います。

BACK INTO ENGLISH

I think I will go to the bathroom.

INTO JAPANESE

私はトイレに行こうと思います。

BACK INTO ENGLISH

I think I will go to the bathroom.