Maybe twin ?🤷🏽‍♀️

I have a question I when to the ER at 6 week because I was cramping and spotting.. I got a ultrasound I seen the my baby with the heartbeat looking good ... so the doctor coke in the room and tell me I have multiple gestation sac?? So I guess they seen a extra sac with fluid but empty.. ok she told me is normal in a twin pregnancy so I’m supposed to do a ultrasound in 2 week to make sure we see something in another sac .. have anyone buy threw this before I’m just nervous 😩