No heart beat

I went to the doctor today and had a vaginal ultrasound. They couldn’t find a heart beat :( I am suppose to be 7 weeks. My doctor said it could be to early to tell or I could be having a miscarriage. I haven’t had any bleeding or any symptoms of a miscarriage. This is my first pregnancy. She wanted me to come back in one week to check for heart beat but i can’t with work schedule so i go back in two weeks. If there’s no heart beat and i don’t miscarry by then they will give me medicine so i can. Hopefully there will be a heart beat. Unfortunately my doctor seemed concerned with a miscarriage. I was so upset with the news. My boyfriend is telling me to stay positive. With this being my first pregnancy and a chance of losing it I now realize how ready I am to be a mom.