13 weeks and bleeding during intercourse

So my husband and I were having intercourse and I know you can bleed from the increased blood flow, but I experienced I’d say a moderate amount of blood that was bright red. It stopped after a few minutes, but it was very scary. We called the doctor and the one on call said if it stopped it’s probably fine and it might’ve even been an external bleed and just come in Monday to get checked out. Anyone else experience this? I’m trying not to worry about it since the doctor didn’t sound worried. It’s my first pregnancy so I’m freaking out on the inside.