Why do I get so depressed right before my period ?

About one week (or fewer) before I get my period, I get really depressed, almost to the point of being suicidal. I become really depressed. One day I’ll be totally amorous, horny, happy, and in euphoria and the next day I’ll be suicidal. I hate feeling this way before I get my period. All I want to do is lock myself up and not talk to anymore. I know it’s because of my hormones and all, but I was wondering how I can stop this ? I feel like I’m bipolar when I’m on it.