Bloating, constipation, cramping, spotting. What's wrong?

I've been bloated the last few days and it seems as if I'm constipated. I have horrible cramping, sometimes it feels like a period cramp but other times it feels like I'm getting sharp pains in my very lower abdomin. I've also been spotting, and bleeding also, it switches between the two. At school, the past 2 days I've been wearing a pantyliner and I spot but when I get home I bleed as if I'm on my period. (I don't really get periods because I'm birth control. I've inly had one period since I've been on it.)