Potential scare

I went to the bathroom earlier today and say some VERY light brown discharge. I checked my cervix (there wasn't enough to see on the toilet paper) and saw more. Called the doctor and they asked about cramping. I don't have any but my blood type is O- so I had to go in for a Rhogam shot. While there I used the bathroom again and my cervix now had night red blood. Again. Not enough to come out. I told them and they did an ultra sound. Baby is just fine measuring where is should be and heart beat is 167. Dr checked an saw blood was coming from my cervix but she said based on everything else there is no immediate cause for concern. She said you can still have a miscarriage even if the baby is ok. Now I'm basically on bed rest but for now ok. Just worried but trusting it's going to be ok. Hope all of your holidays are great and spotting free!