Threatening miscarriage

Went to ER a few days ago and got hcg levels of 8,000 I’m 6 weeks. now today they are only 15,000 when the dr wanted 20,000-30,000 so they said it may be a threatening miscarriage and now it’s a waiting game... any advice or what i should do? Nothing can never be easy for me 😔 I’m so scared now..