extreme pms depression.. please help

Everytime I pms, I get intense depression and mood swings and I have no idea what to do. There is usually no cause but I feel terrible for the 3-4 days. I have insane mood swings and I feel bipolar. It is awful and I just wanted to know if anyone has any tips for feeling like this? I am also on nexplanon and didn't know if this could be a reason why.