YOU SAID:

I have no future or reason to exist.

INTO JAPANESE

私は未来はないか、理由が存在します。

BACK INTO ENGLISH

My future is not exists, reason.

INTO JAPANESE

私の未来は、理由が存在します。

BACK INTO ENGLISH

My future is the reason.

INTO JAPANESE

自分の将来は、理由です。

BACK INTO ENGLISH

My future is the reason.