Zach Bryan Shares Snippet of New Song After Brianna LaPaglia Split

While Zach Bryan's ex-girlfriend is on the bathroom floor crying about their recent split, he's putting out new music ... and it has the makings of a breakup song.

The musician just shared a snippet of a new track on his official Instagram page ... and he's banging away at the piano and singing.

Among the lyrics ... "Recall when we, went to Rockaway Beach, summer heat in eastern Queens, and a subway ride."

Zach also turned the comments off on his IG post ... which is interesting. That's one way to avoid the scorn of Brianna LaPaglia's fans.

Meanwhile, Brianna reeling from the split ... which she says blindsided her Tuesday morning when she woke up to a breakup post from Zach on social media.

As we reported ... Brianna says Zach "discarded" her and she's heartbroken over the end of their relationship.

It looks like Zach's focusing his energy and emotions on new music, possibly inspired by recent events.