God please don't take my baby, not good first US 😢

Dee • my rainbow baby
I went for my first appointment this morning, i was really excited to see my baby, hear the heart beat, then my heart sank when i saw the doctor face. He said he didn't like what he saw, he saw the sac, saw the baby and saw a heart beat, But, i should be 8w5d , and the baby measured 6w1d with a heart beat of only about 60. He thinks "it might be on its way out " he said based on my LMP 3/11, first positive test on 4/12, I should be at the 8 week mark, and highly doubts I could have tested positive at 2 weeks of pregnancy. I go back next week for another US, hopeful the baby is growing and the heart beat is faster, he said he will check me weekly until the baby is for sure ok, or I lose the baby. But he isn't hopeful that the baby will survive. Anyone else have this happen to them? This is my first pregnancy, we have been trying for over 2 years. My cycle is 26-28 days. I'm at a loss of what to think. Next week can't come fast enough!