I've been having dreams I'm having twins I've even revered to them as they?

I keep having dreams im having twins... I find my self refering to the baby as they... And my ob at my 12 week appointment said I can't tell youvif it's twins until your 20 week appointment.. That freaked me out but at both my 16 and 12 week appointment there was only 1.... That we know of.. I'm 18 weeks now,.. My ultrasound is is still 15 days away... Do any of you think it means anythig??? Please no rude comments!!!