Spitting up blood/ pregnancy?

This morning I woke up and I felt the need to go to the bathroom and spit. I do this almost every morning. Well sense I'm so used to it I didnt turn on the light but what I was spitting up was darker. So I turned on the light and it was all blood.. the more I spit the less blood. I was wondering has anyone had this before they found out they were pregnant? Could this be a sign?