Bad news

Had my first appointment and ultrasound and there was debris in the gestational sac. Baby only measuring 6 weeks when my last period puts me at 8 weeks. Heart rate was only in the 70s :(. I have been having light spotting but no cramps on and off a few weeks. It's my first pregnancy and I'm very worried and upset. The OB talked to me and was very mean about the situation. All she said was it will be a miscarriage and all we can do is wait for the heartbeat to stop. So upsetting.