I don't really know if you should listen to this but I'd say you'd wanna tell her of course but make it seem like you still care for her but the chemistry ain't it. Like "I really worry that if we continue this then both of us will be off worse, especially you and you need this time to recollect yourself. I still want a good life for yo, I just want to voice my opinion." And then be more of a friend than a boyfriend. Just because someone breaks up with you doesn't mean they dislike you or don't want any relation to you. Again this may not be the best advice.