Karrueche Tran -- Peace Out, Chris Brown ... I'm Not Raising Your Baby

Karrueche Tran slept on it, and she's decided -- Chris Brown and his baby are not going to be part of her life because she can't take any more drama.

Chris' now ex-GF just reacted to the story TMZ broke -- that Chris has a 9-month-old baby girl -- tweeting, "Listen. One can only take so much. The best of luck to Chris and his family."

As we reported ... the baby's mother is a 31-year-old woman named Nia ... who's been friends with Chris for several years.

Karrueche ended her tweet with a very definitive ... "No baby drama for me."

BTW -- props to KT for the brown baby emoji.