YOU SAID:

i think i need to sleep but im not tired

INTO JAPANESE

私は眠る必要があると思うが、疲れていない

BACK INTO ENGLISH

Think i need to sleep but not tired

INTO JAPANESE

私は眠る必要があるが、疲れていないと思う

BACK INTO ENGLISH

I need to sleep but i don't think i'm tired

INTO JAPANESE

私は眠る必要があるが、私は疲れているとは思わない

BACK INTO ENGLISH

I need to sleep but i don't think i'm tired