lost and depressed

I don't usually post on here, but I have no one else to vent to except you girls. My period throws me into straight depression. It's my hormones, I know, but all I do is cry and I feel like I'm screaming out for help. I have bad thoughts running through my mind day and night, some worse than others. I'm starting to get the feeling that I'm emotionally unstable and I'm going to a doctors appointment tomorrow to talk about possible depression. Everyone around me knows how I've been feeling, and about my appointment, and they're simply acting like it's nothing. My boyfriend gets frustrated with me when my moods switch in a few minutes and just lets me cry, I'm starting to think I'm not built for this world anymore you guys and this is the worst thing I've ever felt. I wan people to care. I want my parents and boyfriend to love me and I don't know how much longer I can hang on feeling like this.