YOU SAID:

I think my dog didn't go to the bathroom last night

INTO JAPANESE

私の犬は昨夜トイレに行かなかったと思う

BACK INTO ENGLISH

I don't think my dog went to the bathroom last night.

INTO JAPANESE

私の犬は昨夜トイレに行かなかったと思う。

BACK INTO ENGLISH

I think my dog didn't go to the bathroom last night.

INTO JAPANESE

私の犬は昨夜トイレに行かなかったと思う。

BACK INTO ENGLISH

I think my dog didn't go to the bathroom last night.