Possible miscarriage

I went for my first OBGYN appointment today and I am 8 weeks. I know when we conceived. The baby measures at 6.5 weeks in the first ultrasound. The doc didn't really give a lot of hope... He did a vaginal ultrasound which confirmed the size. I go back in two weeks to see if the bagmby stopped growing or if the pregnancy is progressing. Has anyone else been through this?  My breasts are still incredibly tender so I feel like my hormones must still be high.