What Do This Scan Test Result During Pregnancy Indicate?

Hello Doctor,Can you please help me as I m pretty much worried about my pregnancy.I m six weeks pregnant as per my scanning report.CRL measured 2.7mm MSD 19.5 mm. But there is no heart beat.I did blood test and everything came positive with no infection like (rubella).Today my doc prescribed me to take Susten 300 orally in the nights for five days.She says ideally the heart beat should be there but we need to wait for next week and check again if we can find it by then and if not then we need to abort. I read about this pill and there are chances of miscarriage and other side effects by having it.Please advise if this tablet is going to help me or not..Looking forward for your reply.