I had sex on Saturday night for the first time. It is now Monday and I am having bright red bleeding, not heavy really but not exactly light either. I bled a brownish thicker blood during sex and a bit more runny yesterday, but it is heavy red now. I also experience severe cramping as well. I have been on birth control for 3 months and I don't get a period so I know it's not a period. I'm severely concerned and have no idea the cause of all this.