12 weeks exactly

Hey so i went too the er because I was having heavy bleeding with no cramping and they checked the baby and baby was fine heart beat good baby was also active. So after that they took blood n got urine!!! My blood n urine results came back ok!!!!! So then they checked my cervix which was closed with no blood around ! N the only thing they can say is a threatened miscarriage and I’m so confused 🤦🏽‍♀️ because i feel like I’m bleeding from something else instead of a possible miscarriage ...