If a medicine doesn’t clearly help, stop it (notify your doctor first). There are other medicines you can try. It doesn’t take much to disrupt the delicate hormonal balance, and many medicines affect it. I found it very helpful to read the “Period Repair Manual, Second Edition: Natural Treatment for Better Hormones and Better Periods” by Lara Briden, which discussed various period-related issues and suggests ways to deal with them. A magnesium supplement every day and a zinc supplement in the latter part of the cycle fixed a lot of my PMS issues and helped a lot with my overall well being.