YOU SAID:
he wants to not feel so good
INTO JAPANESE
彼はとても気分が良くないと思っている
BACK INTO ENGLISH
He thinks he is not feeling very well
INTO JAPANESE
彼は気分がよくないと思う
BACK INTO ENGLISH
I think he is not feeling well
INTO JAPANESE
彼は気分が良くないと思う
BACK INTO ENGLISH
I think he is not feeling well
That didn't even make that much sense in English.