What are some reasons for bleeding if I'm not on my period?

I woke up this morning and there was blood, so I put in a tampon, thinking I was in my period. When I took it out later, there was a decent amount of blood. Later, when I changed it again, there was only a speck of blood. I waited all day, but there was nothing.
Side notes: I am a virgin, and not sexually active. I live a home with my little sister, mom, and dad. It's been about three months since my last cycle. Is something wrong, should I be concerned? Is it normal for blood to stop flowing for a while on a period? Or am I just stressing over nothing? Please help, I am very worried...
What are some reasons for bleeding if I'm not on my period?
Post Opinion