YOU SAID:

I don't know what I was going to say

INTO JAPANESE

私が言おうとしてたのか分からない

BACK INTO ENGLISH

I was going to say I don't know

INTO JAPANESE

私は知らないと言うつもりだった

BACK INTO ENGLISH

Was going to say I do not know

INTO JAPANESE

わからないと言うつもりだった

BACK INTO ENGLISH

Was going to say and do not know

INTO JAPANESE

つもりだったと言うし、わからない

BACK INTO ENGLISH

Was going to say and do not know