I had implantation on August 5th. Went to the doctor on August 8 to confirm the pregnancy and get blood test. They did a vaginal ultrasound and it showed a tiny sac. My hcg was 585. My doctor says it's consistent with early pregnancy and the ultrasound and they want me to get retested tomorrow or thursday. I'm wondering why do they want me to test my hcg level gain if it's normal. Should I be worried. I'm 37 so maybe they think I'm high risk since I'm older?