Surprise!!!! I am pregnant

Alexa
I went to the doctor 10 weeks after I had my son to set up my surgery for my tubal. Well to my surprise we are pregnant. Even though we where done and it wasn't planned we couldn't be more excited. However I had some light spotting right after we found out. They done blood work twice and said my hcg levels didn't quite double but did go up. I went yesterday for a ultrasound and they said the baby is small and the heart rate is slow. Has anyone ever had this happen and went on to have a healthy pregnancy??