I don't know if its tied to bipolar disorder because I've done it when I am in the luteal phase of my period and have severe PMS/PMDD symptoms, and I don't have bipolar disorder.

Just yesterday, I wrote a 3 page angry email. But I didn't send it. I saved it in my drafts. After I had a night to calm down, I rewrote it today when I was more clear minded. It still came across as very upset, but not crazy-level-furious as it was yesterday in tone.