Scared

So today feb 10 is when AF suppose to make her entrance but didn't so I am pregnant went to the doctors today hcg levels are low on ruin sample  😔 did a vaginal somogram to check status of the baby but the doctor said he couldn't see anything I am around 4 weeks today it's sad because he' was saying I might have a miscarage or etoppic pregnancy cause he didn't see anything in my uterus 😞 did a blood test and I have to go back in on Monday to see if my levels increase and if they don't then I won't be pregnant for long ...he said they will keep monitoring me again playing the waiting game has anyone experience this ?