Any other mama’s experiencing these symptoms??

I am currently 15 weeks and went to the bathroom, when I wiped I noticed small amount of brown on the toilet paper. Obviously old blood. It was a bit alarming but I didn’t think it was a huge deal. But now, I’ve started cramping and having some lower back pain. I was scared so I got my Doppler out and checked the baby’s heartbeat and that sounded just fine. Please help ease my mind a little bit. I’m panicking.