Could it be twins?!

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I had my first ultrasound at 8 weeks and we only saw one baby. However, my husband and I found the heartbeat for the first time the other night. At first it was in the 140-150 range and then it went away.. i had to search again and it was in the 170-180! 
Could it be two?! I don't know what to think... We have our next ultrasound on Friday! 🤔😬