I am just about finished with my master herbalist training.
I had a friend that was having this problem mega bad.
Here is what I recommended for her. She said she noticed a difference in about a month and now has no problems whatsoever as long as she follows these guidelines.
The first thing to do is quit eating sugar and processed foods. These cause your hormones to become unbalanced and thus causes the PMS.
Second I put her on Dr. Christopher's hormonal Changeses formula and Wheat Germ Oil for a few months to help get her hormones balanced. I also told her that she needs to faithfully take flaxseed oil and Kelp.
If you are unable to get any of these things in fineland PM me and I would be more then willing to ship these things to you. Blessings Lisa