Multiples???

Went to this place a week later, that gives free first ultrasounds.. They couldnt find a heartbeat, and said maybe it's too early or ectopic.. Ended up in er a week later cause I have hyperemisis. And I was really dizzy and ect. They did another sono and an hcg.. They barely found anything aNd my hcg was abnormally high. So they ordered a serial hcg.. And it didn't double. But did go up. My doctor wanted me to come in asap and do another hcg and sono, they said its one of two things, a missed conception or multiples just really early.. I still have all the pregnancy symptoms and my lower stomach is becoming very big already. (This is my 5th pregnancy. Lost two early on) I'm just very confused.. Anyone else experience this??