St Johns Wort Recommendations?

So I’ve heard that taking St Johns Wort works a treat for PMS.

However I’ve also read and been told not to take it while on birth control such as the pill and the implanon (nexplanon)

I have the implanon and get awful PMS!

I went to a herbal shop and found St Johns Wort and fell in love with what it could do for myself!

Upon reaching the check out the sales advisor asked if I was on any birth control, when I said yes and what I was on he took it away and said don’t get it! You’ll get pregnant!

Instead I got sent home with stupid cat nip ):

Anyone ever Harare similar? Regardless would you recommend it for PMS