PMS! Help!

Hi there! So… I can be good and riding along on my zen horse and then bam! PMS! I am entering perimenopause which has added a whole new flavor to my PMS hormones it seems although… pms has always been a struggle for me. I can go from being calm and happy and fun loving to the wicked witch of the west and I don’t even see it coming. I just totally vomited stuff onto my son about something his dad did and something that would have annoyed me but rolled off my back last week and this week I am finding completely unacceptable. I feel so much shame for dumping on my son. My ex dropped him and my daughter off at my house on his parenting day when I wasn’t home (and he knew I wasn’t home because I was down valley picking up our other son’s phone – as a favor to my ex since it was technically his responsibility) so he could go to the gym. After 3.5 years of this disprespect, however, I have mostly calmed down and accepted that he will never stop doing this, but, when I have pms everything flies out the window and I get triggered all over again. Ugh!!! I guess I have to get stronger than my hormones but they seem to sneak up on me! What should I do? Thanks!