Problems !!!

So I went to the doctors 3 weeks ago after getting 6 positive at home tests. They did a internal ultrasound my first visit and told me there was nothing there , just the sac . Then I go back a week later and she does another internal and says there is a yolk inside the sac now . I got my hgc levels tested and they were rising but no we're near tripplding. : so she told me that I was going to miscarry I was devestated . I went to the doctor again yesterday and she did another internal exam and there was a baby and a heartbeat she's saying I'm 6 weeks 8 days. The heart beat was 109 and she said that was low. So she did more blood work and called me today and said that my hgc levels still did not rise . I don't no what to think. I'm currently bleeding but not a lot . And I'm having cramps like I would have during my period .. is anyone going through the same thing or has gone through this let me no!!!