Week 6 pregnant

Hi everyone... nagpacheck up ako sa obgyne ko last December 26 to confirm the positive pregnancy test . However the doctor only see a gestational sac and it is twin gestational sac . She advice us to come back after two weeks to confirm if the pregnancy is successful. She advice me to have a bedrest. I am afraid because I have already a failed pregnancy last April. But this time i felt more on the symptoms of being pregnant. Should it be a big possible that it will be a successful pregnancy this time.?