Possible twins ?

So had internal ultrasound Friday I am six weeks along doctor found one baby for sure all looking good be he also found something else in the same sac said he could tell what it was maybe a twin but it was close to the baby to make it out doc really wasn't sure said it could be a cysts or a egg that did develop but he felt that it might be producing hormones cause my hcg went pretty high so have to go for another ultra sound at hospital on Wed not knowing driving me crazy anyone have any idea