Pretty sure she is comparing the "love" to a high she is now coming down from... for those of you wondering about the lyrics. Hence the "I still feel the blow..." line, etc.
The song has drug references and blow is slang for cocaine
I'm a aware that Blow is cocaine.
However, in this case she literally means blow as in punch (verb), or hit. As in she felt the pain of the relationship even after it was over. A love hangover if you will.
