need some help/advice

I took a pregnancy test just over a week ago it was positive so i went the doctors and they booked me in for a scan last friday they seen a 2mm sac but no yolk sac or fetal pole so booked me in again on thursday just gone when they scaned me my sac was now 8mm and there was a yolk sac but still no fetal pole my yolk sac looked like a slattered egg the woman  told me it should be a round circle and that because mine was a very odd shape i would miscarry :,( i was told i was between 5/6 weeks ive also got a sist on my overie and my hcg levels only went up by 100 in 48hrs just wanted to here other mums stories and if the pregnancy goes full term will baby have abnormalitys i am only 20 and the doctors didnt explain anything they are just so sure i am going to miscarry :,( x